Raster fix and small colour improvements
Separated interactive code
Renamed ymax parameter to lmax

This parameter reflects the maximum light level to plot and so is more
properly named lmax throughout.
Increased image grey scale resolution.

Presumably images are going to be stored with 256 levels at minimum
anyway, so may as well offer that resolution by default.
Fixed SGAT import.
clean up
Interactive subset selection
typo
Merge branch 'origin/Interactive'