Merge branch 'unique'
Merge branch 'master' of github.com:idris-lang/Idris-dev
Use believe_me for DecEq on primitives

This way, they can compute at the REPL, which is far more useful
behaviour when testing (it is about the only legitimate use for
believe_me in my opinion too :)).
Merge pull request #1496 from edwinb/postulate-deceq

Postulate deceq