The current behavior and syntax of set multiplot ... margins ... spacing is a bit misleading and wrong.
The attached patch tries to fix several points:
left, right, top, bottom to match the order of the set margins command.character or screen units.character units by default (again, see set margins).set margins is, that we can use a single screen keyword to give all four values in screen coordinates: set multiplot margins screen 0.1,0.9,0.9,0.1 ...margins and spacing aren't set togethermargins and spacing, and give more verbose documentation.
