Better "whitespace" checking. #21
Description
Right now, as individual characters goes, only single spaces " " are considered white space, and we tell the parser to skip those in some instances (most importantly when they occur between {{ }} tokens). But sometimes white space is not visible to the eye, causing errors that are hard to spot. Extend the skipWhitespace function to characters that are also considered white space.
The alternative is to make such white space characters visible in the editor. For that, #19 is a prerequisite.