addExternalTileset can now load multiple files at once.
Added error handling when loading multiple tsx files.
Pass PainterScale to MapRenderer, fixing bounding shadows.
Merge pull request #594 from mauvecow/multipletsxload

Allows adding multiple external tilesets at once.
Merge pull request #597 from mauvecow/maprendererscale

Adds painterScale to MapRenderer to fix shadow offset issues for rotated objects.