Separated the Timer A defines from the openMSP430 ones.
Added the "dbg_en" port in order to allow a separate reset of the debug interface.
Added the "core_en" port (when cleared, the CPU will stop execution, the dbg_freeze signal will be set and the aclk & smclk will be stopped).
Renamed "per_wen" to "per_we" to prevent confusion with active low signals.
Removed to missing unused flops when the DBG_EN is not defined (thanks to Mihai contribution).