LES3: Unicode identifiers and operators

[qwertie]

I'd definitely like to support unicode (i.e. non-English) identifiers and additional operators. However, Unicode's guidelines are clear as mud - a lot of terminology is not clearly defined, all documentation assumes familiarity with esoteric rules of unicode, and it is hard to get a visualization of which characters have which properties. (By the way, don't do what I did: I tried my best to install the Unibook Character Browser and failed... not only is the installation process amazingly convoluted, but it just doesn't seem to understand the latest database and therefore ends up non-functional.)

Starting points for this work:

• Unicode's document about unicode identifiers is here
• The main unicode database CSV is here.
• Documentation (for the many files in) the unicode database is here

[qwertie]

To assist, I prepared a table of All Unicode Characters On One Page.