Tidy up setup_eventset()
Tidy up setup_eventset()

Pick a style of retval assignment/comparison and stick with it.
Report papi errors in a uniform way

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