Script compiler: register static functions as "name^argnum" symbol

[ivan-mogilko]

Script compiler registers struct member functions using a "name^argnum" notation. This helps engine to link different versions of API function with extended argument list.

But for some reason same is not done for static functions, which do not belong to a struct. Although it is a common idea that we should move towards having all functions belonging to some type, like under a namespace, there are still a lot of those which are not, and sometimes there's a need to extend their arg list.

Need to investigate if there's any technical reason not to use same registration method for static functions, and if not then register them as "name^argnum".

This problem refers to both new and old compiler, new one is a priority but old should be adjusted to if possible.