Add a pause field to the chamctxt to detect potential deadlock

Add a pause field in the chamctxt structure to check if the runtime is paused when synchronizing the system.

Without this patch, when calling one of the chameleon_sequence_wait() family call, if the runtime system is paused, then Chameleon will deadlock. Thus we automatically resume the runtime system with a warning, and pause again at exit.

Fix issue #105 (closed)