Custom multiplication behavior (option to use \cdot everywhere)

[ZibingZhang]

Description

The current behavior of multiplication is as follows

>>> def f(x):
    return 3 * 5 * x
>>> latexify.get_latex(f)
f(x) = 3 5 x

I personally like having \cdot, and there are other options for multiplication as well: \times, *, etc.

I think we should support specifying the multiplication operator due to the number of options.

Ideas of the solution

Add it as a config option.

[odashi]

#89 was accidentally closed, but this issue should be a part of it.