Support compositional forms

[abrudz]

It'd be nice if this worked:

>> f(x)=2x
>> g(x)=x^2
>> (f∘g)(4)
32
>> (f+g)(f)
24

etc.

See https://www.mathsisfun.com/sets/functions-composition.html and https://www.mathsisfun.com/sets/functions-operations.html

[PaddiM8]

Neat, didn't know that was a thing in maths. Hopefully it isn't too awkward to parse. I guess "if function names are used inside a group (parenthesis), expect an argument after this, and parse the group as some sort of function call". This may happen.