[mod] make associative parenthesis way more involve in taking care of formatting arround him
[fix] correctly dumps associative parenthesis
[enh] make datastructure way more aware of formatting arround them
[mod] same for comprehension structures
[fix] upgrade comprehension and datastructure dumps to fit new structure of node
[fix] special case with comments
[fix] missing formatting in from import (...)
[mod] rename variable
[enh] better handling of print_function
[mod] handle all formatting arround getitem
[mod] adapt getitem dumps to new structure
[fix] make sure this special case pass
[mod] set a default value to print_function option
[fix] special case, not so cool but will work with python3
[fix] in tokenizer, handle print_function situation
[fix] raise can be followed by a comment
[fix] formatting arround star was missing
[fix] formatting can be grouped on colon too
[fix] special case in dumper for the 'not in'
[mod] since 'import' is grouping space for 'from x import y', we need to handle it's preformatting in the context of the 'import x' form