Added experimental no_asserts and no_bounds_query target features.

This can theoretically result in leaner, meaner code, but makes no
performance difference for anything I have tested. I'm pushing it as a
branch so that others can try it if they suspect the assert overhead is
high in their case.
Don't generate assertions inside CodeGen either.
Fix bug in vectorizing allocation.

We weren't actually inserting the new dimension.
REname test to have underscore between two words in name.
Fix HalideProf to build with tricky C++ env. Add rule to Makefile to build it.
Build fix for trunk llvm

We need -lz now.
Move nacl demos to pepper_33

and fix some use of random
Resume tracking trunk pnacl
Peg pnacl version to nacl sdk pepper_33
Add -lz to apps
Add llvm-3.4 to the list of llvms to test
Avoiding triggering needless recompilation of pnacl llvm
Merge branch 'master' into no_asserts

Conflicts:
	src/CodeGen_ARM.h
	src/Lower.cpp
	src/Target.cpp
	src/Target.h
Implemented inf_f32, neg_inf_f32 and nan_f32 for SPIR target.
Passing '-x spir' to clBuildProgram to indicate binary is SPIR.
Merge pull request #270 from jrprice/spir

Fixes for SPIR target
Add explanatory comment for why hex float literals use 64 bits.
Added a static test using one pipeline tiled within another.
Add a static example for how to extend buffer_t with custom fields
Fix bug where trace level 3 would wrap a load inside of an address_of