Update cubio.gd

a little wrong only.
SceneMainLoop -> SceneTree
-=-=-=-=-=-=-=-=-=-=-=-=-=-

*YOUR SOURCE MIGHT NOT WORK*
For mor information on fix:
https://github.com/okamstudio/godot/wiki/devel_scene_tree

Other stuff:
-Shower of bullets demo
-Fixes all around
missing files with fixes for shower of bullets
Fix compilation error on 32-bit linux
Fix AnimationTreePlayer.node_get_input_source typo

- Changed node_get_input_sourcre to node_get_input_source
Fixed documentation typo