Handlers no longer know their path, just their subpaths.

Also added some consistancy things like a '/' at the end of all paths
and every path is lowercase.

 If you go to your browser and type a path in all upper case, it will
still find the correct path. This works for not putting a '/' at the end
of your path in the browser as well.
More documentation!
Merge branch 'path-tests' of github.com:dkuntz2/java-httpserver into path-tests-dk

Conflicts:
	handlers/HelloHandler.java
	httpserver/HTTPHandler.java