in StringMapProperties depricated functions removed
fold and foldWithKey depricated, foldr and foldrWithKey added

cabal test: all tests pass
foldl and foldlWithKey added
instance of Traversable added to StringMap
more inlining in Base
foldl and foldr reexported in Stringmap.Strict
changes to work with data-size-0.1.3
test with testcases with ghc-7.7 and assertNF done

the patched ghc-heap-view-0.5.2 for ghc-7.7 does
not work together with Quickcheck, those tests don't run
generalized union "unionWithConv" added
import of Prelude changed
cabal file refactored: dependency form data-size in conditional compilation, default off

this enables easier test of strictness properties