Dialplans with syntax error should report errors in the console output

After researching the issue, I can at least explain the cause. The default behavior for unhandled exceptions that occur within threads is for the thread to terminate. However, the rest of the application does not. This can mean that exceptions are silently lost.

Some documentation on the issue here:
http://engineroom.mixx.com/2008/07/31/when-rescue-doesnt/
and here (search for "Threads and Exceptions"):
http://ruby-doc.org/docs/ProgrammingRuby/html/tut_threads.html/

One workaround would be to enable Thread.abort_on_exception within Adhearsion itself. For my development purposes, this is exactly what I will do. The downside to this approach is that any unhandled exception within Adhearsions internals can cause the entire application to exit. In my testing, I have already identified several places where this was happening (harmlessly) but the exceptions were never visible.

I propose NOT to change this setting in Adhearsion itself until we have had time to run through more tests and ensure that the application does not throw any internal unhandled exceptions. When we are satisfied that Adhearsion is internally stable, we can enable the Thread.abort_on_exception to allow end-users to be able to debug their applications more easily.