No need to check in types for uniqueness
No need to check LHS for unique usage

Any duplication will be enforced by unification, and won't lead to
sharing itself (does suggest the function will be hard to apply in
interesting contexts though...)
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 #1495 from edwinb/unique

Uniqueness changes
Merge pull request #1496 from edwinb/postulate-deceq

Postulate deceq