creature_birds.txt and creature_subterranean.txt files now use APPLY_CREATURE_VARIATION.

There were differences between how masterwork and other tilesets
constructured birds. This patch brings all of these into line with
each other, and is important in getting BillyJack's less leather
patch to apply.

No other changes are made. In particular it was noted that
ostriches are trainable in some tilesets, but not others.
BillyJack's simple leather mods.

This patch applies BillyJack's simple leather mods to all tilesets:

    http://dffd.wimbli.com/file.php?id=8107
    http://www.bay12forums.com/smf/index.php?topic=132489.0
Added a patch-graphics-from-master.pl

This script makes it easy to take changes from the master raw
directory, and apply it to all the graphics sets on an as-needed
basis.

It's mostly to make my life easier. :)
Updates to Billy Jack's leather 12 Nov

- Fixed an issue with drake scales being tanned
- Fixed Balrog and Dragon Raptor entries appearing as leather types
Distribute simpler leather patches across all tilesets.

See: http://www.bay12forums.com/smf/index.php?topic=133174.msg4763817#msg4763817
Merge branch 'patch_leather' into simple-leather

This distributes Billy Jack's simple-leather patches across
all tilesets.
Merge branch 'simple-leather' into unified

These were already merged by cherry-picks, but this means we commit
makes it easier to keep in sync in the future, and more accurately
reflects the branch state in the history.

Conflicts:
	MasterworkDwarfFortress/graphics/patch-graphics-from-master.pl