closes#12, closes#80, closes#95, closes#96, closes#99
- Issue #12: Set tp_new to NULL for GridPoint and GridPointState to prevent instantiation from Python
- Issue #80: Renamed Caption.size to Caption.font_size for semantic clarity
- Issue #95: Fixed UICollection repr to show actual derived types instead of generic UIDrawable
- Issue #96: Added extend() method to UICollection for API consistency with UIEntityCollection
- Issue #99: Exposed read-only properties for Texture (sprite_width, sprite_height, sheet_width, sheet_height, sprite_count, source) and Font (family, source)
All issues have corresponding tests that verify the fixes work correctly.
