Features from Minecraft 1.7

- Aligned all texture names with minecraft 1.6+ resources;
- Fixed comparator rendering (on/off uses same block ID);
- Added new block type for tall flowers (does not affect rendering);
- Added new tile directive - OVERLAY - to combine multiple textures in
one;
- Added special case for rendering tall flowers;
- Added new blocks: packed iced, tall flowers;
- Updated blocks: poppy(ID:38).