Remember names of deBruijn variables.
Merge branch 'debruijn-names' of https://github.com/ziman/idris into ziman-debruijn-names
Make sure binders are unique before case tree
Merge branch 'ziman-debruijn-names'
Merge branch 'master' of github.com:idris-lang/Idris-dev
Add function name to Codegen errors
Fix error reflection for ProofSearchFail
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 for repeated variables in instance head

Variables should only be brought into scope once! So remove any repeated
variables and only bind them once.
Fix IDESlave reporting of ProofSearchFail
Merge pull request #1255 from david-christiansen/error-reflection

Fix IDESlave reporting of ProofSearchFail
Remove implicit qualifier for 'effect'

Two reasons:

1. The most important: it makes error messages *so much better* :).
Because "effect'" rarely properly fails due to having a very generic
type, so any error arises later and breaks the real error which came
from lift'
2. It is much easier to explain what's going on when documenting
effects!

Apologies for breaking effectful code: I now think it is much better
this way though.
Merge branch 'master' of github.com:idris-lang/Idris-dev
Fix missing function call from 723d972b2
Merge pull request #1256 from david-christiansen/error-reflection

Fix missing function call from 723d972b2
Avoid hole bindings in unification solutions

We assume elsewhere that a hole binding only appears once, and these
aren't really solutions. The addresses #1242 (although the code there
still doesn't type check for a different type class resolution reason).
Can't assume explicit names in updateSolved

Fixes #1242
Modified uniqueBinders function to prevent overlapping binders.