Remove clang from travis compilers
Remove clang from travis compilers

It's not all that useful, since we cover clang by compiling on osx anyway.

Segs/Segs,Segs/Segs,nemerle/Segs,Segs/Segs,Segs/Segs,nemerle/Segs,broxen/Segs,broxen/Segs,nemerle/Segs,Segs/Segs,nemerle/Segs,nemerle/Segs,broxen/Segs,broxen/Segs,broxen/Segs,Segs/Segs,Segs/Segs,nemerle/Segs,broxen/Segs,broxen/Segs,nemerle/Segs