Fix optional combinator in SimpleParser
Some refactoring in CaseOp
Separate case trees for totality checking, compile time and run time
and lift into their own data structure, so that it's clear which one to
use when.

Needs a "make relib"
Merge pull request #467 from Melvar/master

Fix optional combinator in SimpleParser
Merge branch 'color-repl' of https://github.com/david-christiansen/Idris-dev into david-christiansen-color-repl
Merge branch 'master' of github.com:edwinb/Idris-dev
Colourise some error messages

Some error messages are now colourised as well. We assume that all unbound
names are implicit arguments, as the error message doesn't have sufficient
context otherwise.