Compile initial modules with no exceptions
Remove __stdcall for 32-bit opencl

This breaks it on windows, but makes it work everywhere else.
This is a temporary workaround for bug #327
Follow new GPU loop conventions for OpenGL

- set min to zero
- use new block variable names
Merge branch 'master' of https://github.com/halide/Halide
Bugfix to Skip stages

It was lifting calls to images outside of their pipelines in the predicate.
Merge branch 'master' of github.com:halide/Halide
typo fix
Skip gpgpu tests when no gpgpu available.
Prevent bounds explosion during shared allocation size sniffing
Fix return code from gpu_thread_barrier
Very minor fix to OpenCL kernel code indentation.
Only track modulus remainder during simplification if they're interesting.

Mild compilation speedup (~150ms for local laplacian)
Merge branch 'master' of github.com:halide/Halide
Merge branch 'master' into specialize
Dead code elimination.
Add documentation for specialize.