code_tokenize v0.2.0

Major API redesign

code_tokenize in v0.2.0 makes now mainly use of the visitor pattern for parsing the AST

Changes

• tokenize parses source code now by parsing the AST and traversing the AST via a visitor
• custom tokenizing visitors can be defined per language
• For Python, we correct the tokenization process: the indentation is now AST based computed
• Code is extensively tested in parsing large libraries (Python and Java)
• more languages are closer integrated