Checkpoint caching code.
Checkpoint compute_cached implementation.
Add test for compute_cached.
Merge branch 'master' into compute_cached

Conflicts:
	Makefile
	src/Func.cpp
Initial compute_cached support.
Merge branch 'master' into compute_cached

Conflicts:
	Makefile
	src/IR.cpp
	src/IR.h
	src/Lower.cpp
Forgot to add the cache prototype/placeholder.
Checkpoint compute_cached code.
Merge branch 'master' into compute_cached

Conflicts:
	src/CodeGen.cpp
Correctness fixes for compute_cached.

Stores to cache key now take into account that the index to Load/Store
is scaled by the sizeof the type.

The cache_tag support now properly records the expression.
Fix issue with alignment in cache key.

Make cache incorporate buffer bounds in hit test.
Update HelloAndroid for more recent Android SDK
Merge branch 'master' into compute_cached

Conflicts:
	src/IR.h
Allow parallel rvars with a warning
Merge branch 'master' into compute_cached

Conflicts:
	Makefile
	src/Lower.cpp
	src/Schedule.h
Missed in merge.
Couple more merge issues.
Suppress warning about parallelizing rvars when we can prove it's safe.
Allow reordering "pure" rvars.
Made the bad rvar reorder example actually bad.

Before it was technically OK.