lars coordinates

Lars coordinates are messed up somehow. The keywords specifying the location on the disk exhibit different problems: Coordinates are given via two redundant sets of keywords:

1. SHG_LAT and SHG_LON give the Stonyhurst Heliographic Coordinates position in degrees according to the header
2. HPC_X and HPC_Y give heliographic coordinates in arcsec

If these coordinate information sets match up, there should be a steady relationship between them. Plotting reveals some sort of mismatch:

added Bug ~75 labels

moved to issue_collection#1