ALLJOYN-2082 The alljoyn_busattachment_removesessionmember function added

The RemoveSessionMember method has been added tot he C language bindings

The test for this new function was added to the SessionListenerTest since
that test has setup and tear-down that could be reused to test the
alljoyn_busattachment_removesessionmember function.

Change-Id: I3c8dc088b6b560718888eac4a306b3719f0c17ef