Several TH/quasiquote changes
a) Added quasi-quote forms for declarations types e.g. f :: [$qq| ... |] b) Allow Template Haskell pattern quotes (but not splices) e.g. f x = [p| Int -> $x |] c) Improve pretty-printing for HsPat to remove superfluous parens. (This isn't TH related really, but it affects some of the same code.) A consequence of (a) is that when gathering and grouping declarations in RnSource.findSplice, we must expand quasiquotes as we do so. Otherwise it's all fairly straightforward. I did a little bit of refactoring in TcSplice. User-manual changes still to come.