TweenGMS 2 Beta 4.1

This is a small update to the larger Beta 4 release. You can find the post for that update here.

This update fixes an issue where TweenEasy*() functions could cause a crash if called immediately at game start. Additional changes are below...

[4.1]
-Fixed issue where starting an easy tween at launch would cause crash
-Fixed TGMS_FetchTween() to properly return undefined/null tween ids
-Adjusted TGMS_FetchTween to prevent crash if o_SharedTweener doesn't exist yet
-Stopped adding "TGMS" layer to rooms