merge
Merge remote-tracking branch 'upstream/master'
removed untracked file.
Merge remote-tracking branch 'upstream/master'
Merge remote-tracking branch 'upstream/master'

Merge
Merge remote-tracking branch 'upstream/master'
Merge remote-tracking branch 'upstream/master'
Merge remote-tracking branch 'upstream/master'
Fix small bug in simplifier.
Remove llvm-config --cxxflags that gcc doesn't know about.
Merge remote-tracking branch 'upstream/master'
Fix some exponential behavior in the simplifier.

And add a test that it broke.
Minor change to constraint handling in lower that fixes an issue related to constaining output buffers on function with Tuple output. Previously the constraints were not fully used to simplify the output buffers beyond the first one. This change causes constraints on the first buffer to be fully populated through all the remaining buffers.
fixed a typo error in the last changes to lower.
Merge pull request #471 from kree-colemcalughlin/tuple_constraints

Tuple constraints
Test for availability of floating point textures
Fix some indentation
Merge pull request #470 from halide/simplifier_min_max_fix

Fix some exponential behavior in the simplifier.
Tweak script to clean distrib dir before building a distribution
Merge branch 'master' of github.com:halide/Halide