Fix for SitestreamController.getInfo(streamId,userId)

I removed the userId parameter as the twitter documentation does not have such a parameter (see https://dev.twitter.com/docs/streaming-apis/streams/site/control#info). Additionally, the info.json endpoint is an HTTP GET, not a post, and the userId is not actually used by the current code. Lastly, because HttpContants.constructRequest does not sign get requests, all info requests failed. HttpConstants.constructRequests now sign both POST and GET requests if auth is passed.
Deprecated existing getInfo call so as not to break code currently using this method (although it was broken so not likely that many use it)
The addUser and removeUser now support multiple userIds rather than having to add one at a time. The param is passed as user_id=1234,4567,1234,4567 as per docs.
Added preconditions test to enforce maximum number of user_id values to 100 on addUser and removeUser as per docs at https://dev.twitter.com/docs/streaming-apis/streams/site/control#add
Added tests for SitestreamController for the following methods: getInfo, addUser, addUsers, removeUser, removeUsers.
Used more specific Longs.asList wrapper rather than Lists.newArrayList
Updated addUser and removeUser so they do not proxy to addUsers, removeUsers in order to minimize merge issues.
Merge pull request #77 from eldenbishop/master

Fixes for SitestreamController