Hay block fix

- Draw unused hay tiles (data bits) invisible
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).
Features from Minecraft 1.7

- Added red sand
Alpha filler for RGB images

- Converting RGB to RGBA images (for few textures, that have no alpha
channel; yay! happy times!);
- Removed unnecessary textures.
Features from Minecraft 1.7

- Added stained glass & stained glass pane;
- Glass panes connect with iron bars;
- Cleaned up README.
Features from Minecraft 1.7

- New wood, leaves, planks, stairs, slabs & saplings related to new
trees: Acacia, Dark Oak;
- Some changes to block description types;
- Error output clean-up.
Merge branch 'master', remote branch 'akudeukie/mc_1.6'
fixed double_plant* texture names