Improve handling of the space key when typing expressions

[dimitar-asenov]

At the moment the space key is an integral part of expressions, but users often type space in places where it is not strictly necessary in traditional languages, in order to just improve readability. In Envision this causes the parsed expression to include the additional space tokens as errors.

We should find a way to detect these situations and possibly remove the extraneous space characters automatically. The ultimate goal is to allow the user to type code as they are used to and not worry about having too many spaces.