Version 3.50

Fix a major regression that prevented the Eterm and Konsole colors from being correctly snapshotted

Fix a related bug causing incorrect terminal colors after calling :CSApproxSnapshot

Fix a bug causing black to be used instead of dark grey

Have snapshots calculate g:colors_name programmatically

Introduce many tweaks for better speed

Clarify some things at :help csapprox-terminal-example

Default to using our own list of rgb.txt colors rather than searching, for performance.  Add a new variable, g:CSApprox_use_showrgb, which forces us to try finding the colors using the "showrgb" program instead, and fall back on our own list if it isn't available

Remove g:CSApprox_extra_rgb_txt_dirs - not needed in light of the above change

Author: Matt Wozniski