This program will convert a single TARGA-2, TARGA-10, or IMAGINE RGBH file
to expanded TARGA-2 or compressed TARGA-10 output format.

 TARGA-10 output files are RLE compressed, resulting in sigificant size
reduction in most cases.  A command-line arg allows the user to specify how
many significant color-bits are retained, resulting in further compression.