Update some plot %!demos so that they run under Matlab. * datetick.m: Explicitly name 'x' axis in call to datetick. * mesh.m: Use try/catch around block checking __graphics_toolkit__ which is an Octave-only figure property. * patch.m: Call patch with X,Y,C rather than X,Y,PROP,VAL which is not supported by Matlab. * ezplot3: Use explicit call to legend, rather than ';legend;' in ezplot3 call which is Octave-only syntax. * rose.m: Add a demo that Matlab can run. Matlab won't run the second demo which uses Octave-only syntax. * copyobj.m: Don't use errorbar plot style argument which is Octave-only syntax.