WaveBox session cookie support

Patch allows WaveBox to create and send a session cookie along with each successful request.  Added fix to allow UriWrappers which don't contain parameters to be passed as valid.

Process:

1) User logs in, a session cookie is created
2) User accesses API handler, WaveBox checks for session cookie, and will use it for sessionId
3) WaveBox renews user's cookie on each successful API call (DateTime.Now UTC + Settings.SessionTimeout minutes), by injecting a HTTP header just before response is sent.