Add function name to Codegen errors
Merge pull request #1254 from david-christiansen/error-reflection

Error reflection updates
Effect handlers should be covering

They don't make sense if they don't handle all possible operations, and
this can lead to strange errors (one of which I've just been debugging
in Protocols!)
Merge branch 'master' of github.com:idris-lang/Idris-dev
Fix IDESlave reporting of ProofSearchFail