This removes the language specification and BNF descriptions from the
PR release notes (they're too long for that) to a separate document
in the libcom/src/as area. That should be combined into the chapter
on Access Security from the AppDevGuide someday.
Save/restore dbAddr::pfield around callbacks to
avoid corruption if CB forgets to restore.
Need to peak at dbChannel.h during libCom build.
So generate dbCoreAPI.h early, and add extra
-I to source location when compiling dbTrapWrite.c