Increase ParserPickling.version.
Yield expressions are now separate form ReturnStmt.
Simple error recovery in the parser: For now just discard everything that is not a suite or file_input, if we detect an error.
The user context parser should ignore keywords if they are not standing alone.
Make names_dict available in modules.
Move error recovery function.
After error recovery, names need to be removed from the used_names list, because they are not actually defined in the current AST.
Improve Name.is_definition
Playing with params/names_dict
Start to check for name positions with names_dict name finder.
Add the parsers flow information as classes to parser.representation.
Remove a flow information thing for now.
Resolved if/else issues in instances with get_defined_names.

This also means that class tests are now passing, except for private variables, which are not that important.
Parser error recovery simplified. Just fall back to scopes, if somethings wrong.
Small optimizations to make parsing faster.
Splitting up the convert function into leaves and nodes.
Moved the convert function away from pytree
Merged some convert stuff.
convert: run away from tuples.
context is not needed for nodes.