[fitsbits] Coordinate systems for solar image data

[William Thompson]

There's a new update of the paper Coordinate Systems for Solar Image Data 
available at

http://orpheus.nascom.nasa.gov/~thompson/papers/coordinates.pdf

I've tried to take all of your user comments into account.  Let me know if I 
missed anything.

The major changes from the May 13th version are:

1.  Corrected the usage of i and j to match the final WCS paper usage.

2.  Corrected Table 1, in particular the keyword "iVn_m"

3.  Added a section on the use of cylindrical projections for synoptic maps.

4.  Added heliocentric inertial (HCI) from Franz and Harper to Table 4.

Thank you to the people who've reviewed it so far for all your help.

William Thompson