Added matrix multiplication as a performance test
Style corrections
Renamed width to matrix_size
Style corrections
Added a rule to simplify that uses the bounds of min/max expression to attempt to reduce < comparisons to true or false constants in some cases. This is a very useful simplification for the work being done in specialize_branched_loops.
Add a .clang-format that approximates Halide style

Thanks to Daniel Heck for this.
Merge branch 'master' of github.com:halide/Halide
Merge branch 'matrix_mul' of https://github.com/white-pony/Halide into white-pony-matrix_mul
Schedule and formatting tweaks to matrix multiply
Merge branch 'white-pony-matrix_mul'
Lower correctness threshold for 32-bit builds

The scalar version of the code produces quite different results in
32-bit.
Update nacl to pepper_39

This allows for vectorization (as long as the bit-width stays at 128)

Also removed HelloNacl app, because it's a strict subset of nacl_demos,
and not meaningfully simpler.
Merge pull request #539 from halide/simplify_minmax_comparisons

Simplify inequality comparisons against ramps and min/max expressions.
Merge pull request #541 from halide/update_nacl

Update nacl to pepper_39
Added an optional scope argument to expr_uses_var(s). This allows the user to pass in a scope of exprs bound to variables, e.g. from let expressions. The visitor will dive into the bound expressions, whenever a variable in scope is encountered.
Merge branch 'scoped_expr_uses_vars' into linear_solver
After merging in scoped_expr_uses_vars branch, changed has_vars method to use expr_uses_vars and deleted custom visitor.