Xtt sevhist, SevPlotGroup added, PlotGroup and SevPlotgoup in fastavail, preset of layout and timerange, command 'open plotgroup', split digital curves, time range and curve drawing bugfixes

Ge, variable index with [&( )] syntax, display of parent attributes for object graphs iwith .<, window for object graphs works for more than two levels

Xtt open graph, base classgraphs first search for on , then on /data0/x5-5-0/rls/os_linux/hw_x86/xtt/exe