Some minor improvements to run-gdb.sh

Added pid to the name of the gdbinit file, just to make sure that there weren't any collisions.
If set -x is enabled int he file, it will also print out the contents of the gdbinit file.
Merge pull request #243 from dhylands/dhylands-run-gdb

Some minor improvements to run-gdb.sh
Merge remote-tracking branch 'upstream/master'