[Kst] [Bug 111114] Ability to apply only settings that were changed in plot dialog

[Barth Netterfield]

The data object dialogs (vectors, curves...) work very well for this for the 
other objects, and are very useful.   Given this, for consistency, we could 
just make the plot dialog work the same as the object dialogs - eliminate the 
'all windows' and 'all plots' buttons, and add an edit 'multiple button'.

Scripting is a great addional method, but won't be that common, I guess.