Now
===

- (Python 3.0) non-ASCII identifiers. Also str.format should be updated;

- (Python 3.0) support for b"..." syntax and remove u"..." syntax. Also all
  escapes need to be updated;

Later
=====

- Highligh errors where symbols follow by numbers like this: 0o123LaB

- Need more accurate way to handle indentation errors. For example
  mixing spaces and tabs may be used for pretty formatting;

- Need more checks for errors like: absent brackets, absent quotes,
  back slash at the end of strings;