ENABLE_pygw=ON by default since (within well-defined constraints) it now works again.
ENABLE_pygw=ON by default since (within well-defined constraints) it now works
again.

Implement version check for pygtk-2.0 to see whether it is compatible with
the Numeric/numpy choice by the PLplot user.  If not compatible, a warning
message is issued, and ENABLE_pygcw is set to OFF.


svn path=/trunk/; revision=9217

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