Request for asynchronous API

[kent-cheung-arm]

As tool developers, we would prefer an asynchronous API to better manage long-running calls to the library. For example, calls to cti_launchApp/cti_launchAppBarrier and cti_execToolDaemon could take several minutes depending on the size and number of dependencies of the associated binaries. Additionally, a method to poll the progress of/cancel an in-progress call of those long-running methods would be very useful.

The primary benefit for our tool would be that API calls can be made on the main (GUI) thread without blocking the GUI for the user.