* Fix for wild card import statements (e.g., "from Freestyle import *") was done.
Now import statements are either without using "from" or with all imported names
explicitly listed.
* GNU GPL header blocks were added to Python programs. Additional code clean-up
was also made.
* Removed freestyle_init.py and extra-lines.sml that were no longer used.
* Proper handling of keyword arguments was implemented in Operators and ContextFunctions,
as well as in methods of Interface0D, Interface1D, Iterator, their subclasses, Noise and
IntegrationType.
* Operators' methods and functions in the ContextFunctions module were renamed from
CamelCase to lower cases + underscores. Style modules were updated accordingly.
* Additional code clean-up was also made.
* The API syntax of StrokeVertex and StrokeAttribute was updated by means of getter/setter
properties instead of class methods. Python style modules (including the Parameter Editor
implementation) were updated accordingly.
* Code clean-up was done for a few Python style modules, mostly by removing duplicated
definitions of stroke shaders and fixing indentation.
