v0.15alpha4

Big changes

• Added a new menu for batch-configuration of the force_invisible property
• Added automatic keyframing for force_invisible and stale custom properties because it was extremely confusing
• Implemented import and export of shadow volumes. Now you can edit shadow and add the new ones #18

Other improvements

• Reflections are now displayed in Blender the way they are in the game
• Made import more robust so some models from old mods are now imported correctly
• Improved automatic force_skinning

Fixes

• Fixed some errors in the "Attach to armature" operator
• Removed some unnecessary warnings #17
• Ignored encoding errors by default
• Removed import of vertex groups for xreffed meshes