(TK-43) Fixy query param issue with proxy

Previously, a proxy handler added to a server would crash when
given a query parameter. Fix this issue and add test to validate
it works.
(TK-43) Address comments on PR

Change URI to be a StringBuilder to preserve as much of
old code as possible. Add additional query params test. Further,
change some variable names in tests and docs.
Merge pull request #44 from fpringvaldsen/TK-43-proxy-fails-query-param

(TK-43) Fix query param issue with proxy
(PDB-671) Enable JMX support for Jetty 9

This patch enables JMX support for exposing Jetty 9 metrics.

I've introduced a new configuration item `jmx-enable` which is a string based
boolean configuration item. It defaults to `true` which enables JMX support
by default.

Signed-off-by: Ken Barber <ken@bob.sh>