revised pgplottingframe.py to first try  to import the (deprecated) matplotlib.backends.backend_tkagg.NavigationToolbar2TkAgg, and if the import fails, to  import the newer NavigationToolbar2Tk instead
revised pgplottingframe.py to first try  to import the (deprecated) matplotlib.backends.backend_tkagg.NavigationToolbar2TkAgg, and if the import fails, to  import the newer NavigationToolbar2Tk instead

popgengui/negui,popgengui/negui,popgengui/negui,popgengui/negui,popgengui/negui