can we FINALLY do filter?
Merge pull request #289 from ucsd-progsys/constraints

Logical Constraints
asdads
Merge branch 'master' of https://github.com/ucsd-progsys/liquidhaskell
haha, looks like tests/todo/filterAbs.hs works
haha, looks like tests/todo/filterAbs.hs works
Update filterAbs.hs
haha, looks like tests/todo/filterAbs.hs works
Merge branch 'master' of https://github.com/ucsd-progsys/liquidhaskell into constraints