Add stanza so that installed xw??.py functions are not executable.  (Like x??.tcl, they cannot be executed on their own, and instead are used by other executable scripts such as pythondemos.py or prova.py.)
Add stanza so that installed xw??.py functions are not executable.  (Like
x??.tcl, they cannot be executed on their own, and instead are used by
other executable scripts such as pythondemos.py or prova.py.)

svn path=/trunk/; revision=3545

FreeScienceCommunity/PLPlot,FreeScienceCommunity/PLPlot,FreeScienceCommunity/PLPlot,FreeScienceCommunity/PLPlot,FreeScienceCommunity/PLPlot,FreeScienceCommunity/PLPlot,FreeScienceCommunity/PLPlot,FreeScienceCommunity/PLPlot,FreeScienceCommunity/PLPlot