:help and tab completion for :doc
Inlining - Evaluator now supports run-time terms

In particular this reduces type class overhead.
NOTE: Breaks the javascript code generation because it doesn't seem to
support projection from global names, which can now arise as a result
of inlinings.

A temporary fix for this would be to update ElabDecls.hs:733 to
simple_rt ctxt t = t

which disables the simplification of run time terms.
Merge branch 'master' of github.com:edwinb/Idris-dev
Merge pull request #597 from jfdm/master

Added documentation for builtins. Rewrite tactics not documented.
Merge pull request #598 from david-christiansen/docs

:help and tab completion for :doc
Documented the remainder of System.idr