Add typedefs for new callbacks to be used by cairo_current_path: cairo_move_to_func, cairo_line_to_func, cairo_curve_to_func, and cairo_close_path_func.
cairo_path.last_move_point and cairo_path.current_point are now fixed-point not doubles for consistency.
Now accept 4 explicit function pointers rather than a structure. Eliminate unnecessary done_path callback.
Track change in _cairo_path_interpret. Code previously in done_path callback is now here immediately after call to _cairo_path_interpret.
Internal _cairo_path API modified to accept fixed-point data everywhere. Much cleaner this way.
Have to convert doubles to fixed-point to track changes in _cairo_path API.
Keep data in fixed-point rather than going through intermediate doubles. Track changes in _cairo_path API.
New function to help when working with freetype.