IterativeDeepening.hs rewriting. Still broken.
Removed pipes that break haddock parsing.
Started more extensive monadic refactoring of IDA* implementation.
Modifications to cabal file.
Merge remote-tracking branch 'upstream/refactor' into refactor

Conflicts:
	core/src/Strappy/Core/Expr.hs
	core/strappy-core.cabal
housekeeping (white space, comments, formatting)

The changes here are just formatting changes and shouldn't involve any
signficant changes to the functionality of any of our code.
rewrite sampler, use monadTs in high-level code

This commit includes a refactoring of the probabilistic sampler and more
extensive use of monad transformers, particularly in the
simulation-level code.