python-reimpl: before parsing file strip all comments
python-reimpl: handle @import
python-reimpl: parse properties, parse values (at least provisional)
python-reimpl: compile properties in extra function
python-reimpl: parse defines from mapcss file
python-reimpl: compile properties, simplify code (use single 'to_use' var)
python-reimpl: compile properties: handle prop type 'tag_value'
python-reimpl: compile_selector_part(): fix indentation
python-reimpl: parse/compile conditions
python-reimpl: Move database connection to module db.py
python-reimpl: transliterated eval parser
python-reimpl: compile eval statement
python-reimpl: func all_scale_denominators(); make sure every selector has min/max scale
python-reimpl: compile get_where function
python-reimpl: @postprocess
python-reimpl: 'stat'-functions

get ...
- all scale denominators
- all properties
- all values of a property
python-reimpl: implement @depend_property, @values, @default_other
python-reimpl: better naming scheme for function compile functions
python-reimpl: implement match function
python-reimpl: process mapnik: replace columns in mapnik file