Added EXTRA_DIST for including the octave demo files into the tarball with "make dist".
Added EXTRA_DIST for including the octave demo files into the tarball with
"make dist".

svn path=/trunk/; revision=4358

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