Add cmake logic to turn of the memqt device if Qt is not installed, untested.
Add cmake logic to turn of the memqt device if Qt is not installed, untested.

svn path=/trunk/; revision=11213

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