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.
Merge branch 'master' into compute_cached

Conflicts:
	src/IR.h
Merge branch 'master' into compute_cached

Conflicts:
	Makefile
	src/Lower.cpp
	src/Schedule.h
Missed in merge.
Couple more merge issues.
Merge branch 'master' into compute_cached

Conflicts:
	Makefile
	src/Schedule.cpp
	src/Target.cpp
Merge fixes.
Add cuda compute capabilities 3.0, 3.5, 5.0

Untested.
Update in response to discussion. Still untested and unsuitable for merge.
Don't try sliding window on functions that have compute_at == store_at