Fix a bug where integer constants were not getting casted to correct type when
generating x86 intrinsics during peepholing.

Add test for above.

Untabify simd_op_check.cpp.
Disabled print test on windows. It only works with trunk llvm.
Prevent static destructor crashes with ptx/opencl

1) Leak the static contexts because the destructors might get called late
2) Early-out from dev_free if there's no device pointer. Otherwise acquiring
the context barfs.
3) Add an actual error message when a Buffer destructor fails to clean up a
device allocation.
Merge branch 'master' of github.com:halide/Halide
Removed environment variables from acquire/release test.
Further fixes to lossless_cast. Also ensure it returns a value
properly casted to the target type.

Add simd_op_check cases, including one that doesn't work yet.
Merge branch 'master' of https://github.com/halide/Halide
Remove apps/HelloAndroid/jni/halide

Compilation by-product that should not have been checked in to source
control
Promote casts inside lets for peephole matching
Improve error message and docs for common color index problem in GLSL.
Fix bad doxygen ref
Merge branch 'master' into fft_optimizations
Merge pull request #372 from halide/fft_optimizations

FFT optimizations/bug fixes
Fix readme typo
Merge branch 'master' of github.com:halide/Halide
Target::has_gpu_feature() should return true for OpenGL
cherry-pick some cleanups from pull request #370
Merge branch 'master' of github.com:halide/Halide
Clarify why has_gpu_feature doesn't count OpenGL
Add ability to programmatically set HL_TRACE_FILE