add a .* if the key is unset

This allows an action with a nil key. The regex engine is probably smart
enough to optimize this away if its at the end, so no perf impact in
cases where it's not needed.
enable specs that should work now
add missing spec support class
move registry examples to a shared example group

Easier to test other objects that inherit from Registry
correct name of lock var
move respond_to specs out of shared registry examples

Configuration responds to everything, so it can't pass that test.
add Configuration specs