VectorMathNode, ScalarMathNode, Areanode bugfix

New node: Vector math node
Vector math, cross, dot, add, distance, length, sub

Math Node, provides f(x), f(x,y) and constants pi and e as nodes. Renamed to match other classes.

Bugfix for output of AreaNode to make work like Range and Series [a b c d] instead of a b c d which fixes compatibility problems with vector in node.