Work on Headers

Made metering headers only send on non-failure.
Attempt to make Location header relative, but this fails. See
http://bit.ly/1cGD7Vc. This can be shown to fail by changing the
getPath() on line 82 of StreamResourceTest to toString().
Make a test class for the header filter. Property setting causes
concurrency issues due to static config in main class, so the methods
are commented out. Will consider making the properties a passed
dependency instead.