Added new IsSpokesInstalled logic

* Version 1.0.22:
* Date: 28th June 2013
* Compatible/tested with Spokes SDK version(s): 2.8.24304.0
* Changed by: Lewis Collins
*   Changes:
*     - Added new IsSpokesInstalled convenience function. You can
optionally call this before
*       calling the Spokes.Instance.Connect method to check if Spokes is
installed.
*       It is called by default anyway when Connect is called so that if
Spokes is not
*       installed, Connect will immediately return false (failed to
connect), rather
*       than cause a timeout waiting for COM Object to instantiate (and
fail).