Future-proof the TC' monad

In GHC 7.10 Monad instances will need to implement Applicative
and MonadPlus instances Alternative.

Just reuse the corresponding functions on the Monad/MonadPlus instances.

Fixes #1181
Improve ideslave highlighting of primitives
Merge pull request #1203 from david-christiansen/ideslave-printing

Improve ideslave highlighting of primitives
Merge pull request #1200 from melted/tc

Future-proof the TC' monad
Make ':doc' say 'No constructors.' when a data type has no constructors.
Merge pull request #1206 from paulkoerbitz/fix/1187-doc-no-constructors

Make ':doc' say 'No constructors.' when a data type has no constructors.