Minor change to SpecializeClampedRamps.cpp that applies the mutator recursively until the stmt is fixed. This allows us to specialize all of the clamped ramps rather than just the outermost.
Reuse current SpecializeClampedRamp instance for recursively mutating the stmt.
Force a GPU flush in using the gpu tutorial.

Otherwise it could finish timing before doing work on some platforms.
Changed SpecializedClampedRamps to produce a single if stmt, rather than multiple nested stmts.
Merge pull request #446 from kree-colemcalughlin/specialize_all_clamped_ramps

Specialize All Clamped Ramps
Merge branch 'master' into target_features