fix judgment message param Tracks for holds
allow button messages in SSM's SelectMenu

This allows themers to make use of SelectMenuInputMessageCommand even
if they have SelectMenuChangesDifficulty set to true in their Metrics.

Neither _fallback nor Default use SelectMenuInputMessageCommand and,
for that matter, no theme I'm aware of does (perhaps because it's
essentially inaccessible as it is).

I use this to detect if a player presses START while holding SELECT on
SSM.  This is possible with the existing code system, but that
CodeMessage does not fire until the player lets go of both buttons.
This allows the themer to check for that button combination more imm
ediately.
Merge pull request #185 from dguzek/master

allow button messages in SSM's SelectMenu
update URL to github address
Merge pull request #183 from sigatrev/judgment-message-tracks

fix judgment message param Tracks for holds
Exposed StepMania::SaveScreenshot to Lua.  Added prefix and suffix args.  Removed unused index arg.  Removed hungarian notation.
Merge branch 'screenshot_exposure' into kyz_current
Added documentation for SaveScreenshot and Profile:AddScreenshot.
Merged documentation conflicts.
Fixed reversed success return from SaveSacreenshot.  Added PlayerStageStats:GetHighScore Lua function.