Add new argument type, eArgSignalName,

Add missing break statment to case statement in Process::ShouldBroadcastEvent.

Add new command, "process handle" to allow users to control process behavior on
the receipt of various Unix signals (whether the process should stop; whether the
process should be passed the signal; whether the debugger user should be notified
that the signal came in).

llvm-svn: 116430