Added a ping interval on the client to ensure that auth tickets do not expire when there's lack of activity.

- This also involved adding a new configuration option 'pingInterval' which can be set via seconds

#1998
Added tests to verify that pingInterval behaves correctly with different configuration options in addition to multiple connection starts and stops.

#1998
Updated tests to utilize the new ping server signature
Changed the pingInterval configuration value to be in milliseconds.
Addressed code review comments

- Changing an error message to not be prefixed with "SignalR:" and adding a log for it.
- Added a failsafe to the ping server common utility so that if there is no transport defined we instantly reject the deferred (essentially nooping).
Addressed code review comments.

- Removed the connection stop from a ping interval fail.
- Modified the ping interval fail to use the new js error resources.
- Removed the test that ensured that a failed ping interval would stop the connection.