Centralize path magic in apiserver into the New method

Make OperationHandler and WatchHandler properly encapsulate their
concerns and make them not depend on the global path
Merge pull request #835 from smarterclayton/apiserver_cleanup

Centralize path magic in apiserver into the New method
Add more parameters to Watch

* Add labels selector (same as List)
* Add fields selector
 * Plan to let you select pods by Host and/or Status
* Add resourceVersion to let you resume a watch where you left off.
Allow more general parameters to be made by client. Also fix style and comments.
Add fake client to make testing easier.
Add WatchReplicationControllers to kubecfg's fake
Make replication controller use client
Simplify ResourceWatcher interface to one function.
Prevent accidental setting of sync or timeout