REP-1283 DeRP Filter

I'm not sure if system level tests will be necessary for this story? Since I can actually test the Java filter API doFilter method, my unit tests are fairly comprehensive and can be expanded to cover more cases. Actually, I suppose we need a test for the response messaging service, at least.

Note: The tests won't pass on this branch until we cut a release of http-delegation. We should also probably update the version api-checker uses.
Fair enough. I included the Bean part to further differentiate between this class and the HttpDelegationHeaders class (which is simply an enumeration of the header names we use). If we drop the Bean part, shoud we re-evaluate the name of the header enum class or package structure?