add support for watching directories for changes in files
ignore certain file patterns when watching for changes (for example, autosave files)
add TestError variant, for when things are broken, not just wrong
switch to streaming interface for reports, so that test results can be shown as the tests are run

Conflicts:
	snap-testing.cabal
	src/Snap/Test/BDD.hs
version bump - 0.4.0.0