Attempt at fixing hang in promise.

The specific case that causes an issue is Cont#eval,
that results in Unfulfilled and then later errors out.
This meant the error handling chain was broken,
and Promises waiting on a result would never be
completed (or broken).

Fixes #267.
Merge pull request #313 from scalaz/topic/promise-deadlock

Attempt at fixing hang in promise.
build against 2.9.3
added uncurried versions of foldRight1 and foldLeft1 to Foldable1Syntax
Profunctors.
Fixed MVar retry behaviour.

Shadowing for the loss. When retrying it incorrectly
used the last value it saw rather then the value it
was attempting to write.

Fixes #314.
Added note to MVarTest.
add `Profunctor` to `GenTypeClass`; tuned
disable test for `Traverse[Zipper]`, since it causes memory leaks