Editor improvements: input floats like “pi/2” or “2+2”, context menu for “Output”, ne

[DP News-Robot]

A small convenience when writing float values: you can input an expression, like pi, pi / 2 or 2/3 instead of typing the actual value (3.14…, 1.57…, 0.6666….). Any expression using CastleScript is allowed. This is nice e.g. for angles for which we use radians (consistent with X3D, OpenGL, many other APIs). So you have …