chore: Enable building with stable rustc again on travis
chore: Enable building with stable rustc again on travis

With 1.11 released building on stable should no longer trigger timeouts.

# Conflicts:
#	.travis.yml

Marwes/embed_lang,Marwes/gluon,Marwes/gluon,Marwes/embed_lang,gluon-lang/gluon,gluon-lang/gluon