Find the standard color of an unknown star.
  colorsol, stand,fil,jd,am,serial,inst,instsig, $
             color1,color2,trans1,trsig1,jdref1,trans2,trsig2,jdref2, $

  stand    - String array of standard names.  (See coord.)
  fil      - String array of filter names for observations.
  jd       - Double precision array of the JD of observations.
  am       - Floating point array of the airmass of observations.
  serial   - Serial number of observation.
  inst     - Instrumental magnitude
  instsig  - Uncertainty of the instrumental magnitude
  color1   - Name of filter for the first color.
  color2   - Name of filter for the second color.
  trans1   - Transformation coefficients (vector) for first filter.
                trans1(0) = principal extinction coefficient
                trans1(1) = second order extinction coefficient
                trans1(2) = color term
                trans1(3) = zero-point
                trans1(4) = time-dependent extinction term
     if provided:
                trans1[5] = (f)  airmass squared term
                trans1[6] = (g)  color squared term
  trsig1   - Uncertainty on the transformation coefficients (vector).
  jdref1   - Time reference point for extinction (first filter).
  trans2   - Transformation coefficients (vector) for second filter.
  trsig2   - Transformation coefficients (vector) for second filter.
  jdref2   - Time reference point for extinction (second filter).

     tran and transig can either be 5-element vectors or 5xN element arrays.
                must match the number of transformation sets provided
  BADFLAGS - Array of flags that mark data bad (if true).
  DATABASE - Name of MYSQL database to save reduced observations.
                 The default is 'phot'. 
  DB       - Flag, if set, reduced observations will be saved to database.
  DVERBOSE-  Code for dbphot and other routines for db transaction verbosity.
  FILTER1 -  Name of the first filter
  FILTER2 -  Name of the second filter
  FULL    -  Flag, if true, will enable the complete printout, otherwise
                just the final summary for each object will be printed.
  NOEDIT  -  If set, suppresses the interactive editing of the star data.
  NOPRINT -  Flag, if true, will inhibit the summary printout to the screen.
  PATH    -  If SAVE is set, this points to the directory where
                results should be written.
  REFAM - Optional air mass reference for the transformation.  The default
             is an airmass=0.
  REFCOLOR - Optional color reference for the color term transformation.
                 This term is normally C * (B-V) or some other standard
                 color.  As written, the reference color is zero and this
                 is the default.  By providing this value you are using
                     C * ( (B-V) - REFCOLOR ) for the term instead.
  REFID -    String uniquely identifying observing run. This is used in 
               updating the data table with the reduced observations in the 
               database. It must be specified if DB is used.
  SAVE    -  Flag, if true, will save the final photometry to an output file,
                and, if DB selected, to database.
  TABLE    - Name of table in MYSQL database to save reduced observations.
                The default is 'data'. 
  TIDX     - Indexing array, same length as the input observations.  This
                keyword is ignored if the input transformation vectors is
                a simple 5-element vector.  If the transformation is provided
                as a 5xN array then this keyword is REQUIRED.
             Each element gives the index into the set of transformation
             values.  This allows combining data that have different
             photometric transformation coefficients.

  RA       - Measured right ascension of object in that observation.  Do not
                use a catalog or ephemeris position, only real astrometry.
                default=no position, only needed for saving to database
  DEC      - Measured declination of object in that observation.  Do not
                use a catalog or ephemeris position, only real astrometry.
                default=no position, only needed for saving to database
  object    - Name(s) of program object.
   std1      - Standard magnitude of first filter.
   stdsig1   - Uncertainty of the standard magnitude.
   std2      - Standard magnitude of second filter.
   stdsig2   - Uncertainty of the standard magnitude.
   stdcol    - Standard color, first filter - second filter.
   stdcolsig - Uncertainty of the standard color.
 Data for objects completely removed from colorsol reduction due to bad
 flags will not be removed from the hard files.
  Written by Marc W. Buie, Lowell Observatory
  96/11/25, MWB, added PATH, SAVE, FILTER1, and FILTER2 keywords
  97/02/11, MWB, added new transformation support (k(t))
  97/02/25, MWB, added NOEDIT keyword and actions
 2006/08/14, Peter L. Collins, Lowell Observatory
             add database support (save reduced observations) and header cleanup.
 2006/09/26, PLC, add INSTRUMENT keyword to pass through to dbphot.
 2006/10/17, PLC, modify effect of SAVE flag to control db update also.
 2006/12/07, PLC, replace instrument and rundate keywords by REFID and
                   change calls to dbphot.
 2006/12/10, PLC, fix bug involving TABLE not passing through to dbphot.
 2006/12/28, PLC, add DVERBOSE keyword, add 1 additional entry to 
                  the db data table per object for the solved color value, and
                  fix handling of hard files for refid length.
 2007/01/04, PLC, further fix for the hard files.
 2007/02/05, PLC, fix for adding color name to database entries. Improve logic
                  for bad flags and data scrubbing.
 2013/06/02, MWB, updated to support different transformation coefficients
                  for the input data.
 2013/06/18, MWB, added RA, DEC keywords
 2013/06/25, MWB, added REFCOLOR keyword
 2014/03/05, MWB, added REFAM keyword, added full set of second order terms
 2014/05/20, MWB, fixed bugs with array input for trans1 & trans2
 2015/10/10, MWB, fixed bug with color/colorsig indexing during solution