sample PMDA - add helper script get_next_pmid
sample PMDA - add helper script get_next_pmid

Scans the PMNS to find the next bunch of unassigned PMIDs.
Just for the sample PMDA which has grown to the point where
it is not immediately obvious which PMIDs have been used.

aeg-aeg/pcpfans,prasincs/pcp,prasincs/pcp,adfernandes/pcp,wuliming/pcp,mbaldessari/pcp,andyvand/cygpcpfans,adfernandes/pcp,edwardt/pcp,wuliming/pcp,aeg-aeg/pcpfans,edwardt/pcp,andyvand/cygpcpfans,andyvand/cygpcpfans,prasincs/pcp,wuliming/pcp,prasincs/pcp,aeg-aeg/pcpfans,aeg-aeg/pcpfans,edwardt/pcp,aeg-aeg/pcpfans,aeg-aeg/pcpfans,wuliming/pcp,adfernandes/pcp,aeg-aeg/pcpfans,mbaldessari/pcp,prasincs/pcp,mbaldessari/pcp,adfernandes/pcp,andyvand/cygpcpfans,tjanez/pcp,edwardt/pcp,adfernandes/pcp,andyvand/cygpcpfans,aeg-aeg/pcpfans,andyvand/cygpcpfans,mbaldessari/pcp,edwardt/pcp,wuliming/pcp,edwardt/pcp,mbaldessari/pcp,adfernandes/pcp,edwardt/pcp,adfernandes/pcp,mbaldessari/pcp,tjanez/pcp,andyvand/cygpcpfans,wuliming/pcp,tjanez/pcp,tjanez/pcp,prasincs/pcp,adfernandes/pcp,wuliming/pcp,andyvand/cygpcpfans,tjanez/pcp,wuliming/pcp,tjanez/pcp,tjanez/pcp,edwardt/pcp,prasincs/pcp,prasincs/pcp,tjanez/pcp