Eliminate "p" examples from test because they user higher-level octave programming that demands octave-2.1.50 or better (which not all users have).
Eliminate "p" examples from test because they user higher-level octave
programming that demands octave-2.1.50 or better (which not all users have).

We have kept the remaining "x" examples for this test.  They are worth
having since they directly test the octave interface to libplplot and they
work for octave-2.0.x or later.

svn path=/trunk/; revision=5098

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