SCI: improved script patcher

Gabriel Knight + King's Quest 6 patches now also work for Mac versions of those games
added support for selectors instead of using hardcoded values
Merge branch 'master' of github.com:scummvm/scummvm
SCI: little comment cleanup
TSAGE: R2R - Renaming in scene 1580
TSAGE: Renamings for R2R Elevator shaft bottom
TSAGE: Renaming for R2R spill mountain shaft
TSAGE: R2R - Renaming in scene 1625
TSAGE: Renamings for R2R Spill Mountains elevator
TSAGE: R2R - (incomplete) renaming in scene 1800