Add shader implementation of alpha test
Force walk animation when flying (Fixes #2015)
Fix NpcAnimation non-existing skeleton crash (Fixes #2028)
Treat "Root Bone" as the animation root if existing (Fixes #2019)
Disable travis IRC spam until the OSX build is fixed
Ignore some extra string arguments to ShowMap (Fixes #2029)

Required for a dialogue result script in Morrowind.esm ("ShowMap Dren Plantation").
This must do the same as "ShowMap Dren", which actually does work properly, since ShowMap supports partial string matching.