.travis.yml: Allow OS X builds to fail.
.travis.yml: Allow OS X builds to fail.

There still seem to be some codegen failures on OS X.

gaussian-blur and something in runtests.jl are breaking.

JuliaPackageMirrors/ParallelAccelerator.jl,IntelLabs/ParallelAccelerator.jl,malekbr/julia-to-tiramisu