* interrupts.t: Rework logic that decides when to call
_Thread_Dispatch. Analysis by Sergei Organov <osv@javad.ru>
determined that _ISR_Signals_to_thread_executing was not being
honored and/or cleared properly.
* SUPPORT, LICENSE: New files.
* Numerous files touched as part of merging the 4.5 branch
onto the mainline development trunk and ensuring that the
script that cuts snapshots and releases works on the documentation.
