ALLJOYN-1710 subtask ALLJOYN-1798 Implement setlinktimeout in C

This code includes basic unit tests for the
alljoyn_busattachment_setlinktimeout and the
alljoyn_busattachment_setlinktimeoutasync functions.
The unit test only test that the bindings actually call all of the
way through to the underlying C++ methods.  It does not test that
when setlinktimeout is set that the daemon will actually drop an
unresponsive session.

Change-Id: I8369dfda945de60cea3511bb495061436200cb42
ALLJOYN-1710, subtask ALLJOYN-1791 Add Async AuthListeners to C binding

The alljoyn_authlistener is now passed as one of the parameters for the
alljoyn_authlistener_requestcredentialsasync_ptr and the
alljoyn_authlistener_verifycredentialsasync_ptr.  The reason for this is when
using the async authlisteners the user is required to always call the
corresponding response functions that require the alljoyn_authlistener as one
of the parameters. If this parameter were not passed in the user would have to
pass in the alljoyn_authlistener as part of the context or make it a global
value.

Fixed memory leaks and compiler warnings seen when using the gcc compiler and
valgrind.

Change-Id: I43b358f6353372a3e7ecf1a8611cf3395bcc74bf