Add support for Quartz ore and redstone block

See #863
First pass an rendering comparators

See #863
Load textures from the new textures folder (intead of terrain.png)

See #863
Handle HD textures and animated textures
Weighted pressure plates

See #863
Support for the Daylight sensor

See #863
Added:
-droppers (still TODO vertical orientations)
-activator rails
-quartz stairs
-trapped chests
-quart blocks (all types)

Also moved restone block and quartz ore block code to the end of the file.
Redstone now connects to trapped chests.
Updated png-it.py, now it has --autocrop option.
1.5 Pre-Release updates/fixes
Fix for Ender Portal Frame, w/eye of ender, in all orientations
Minor fix for Comparator back torches
Update to lighting on Quartz stairs
Added Quartz Half Slabs
Added Hoppers
Screenshot: http://i.imgur.com/nB2Nzp6.jpg
Merge pull request #895 from skeight/snapshot

1.5 Pre-Release updates/fixes
- Fixed lighting for anvils.
- Added vertical orientations for dispensers and droppers
- Added special cases of stone and sandstone double slabs
Merge branch 'snapshot'