[tcaxPy] Multiple ASS Style Support

milkyjing

To add the support of multiple ASS style and avoiding the modification of the TCC file, we can use the inherited ASS header, see http://www.tcax.org/forum.php?mod=viewthread&tid=54.

And to ease the access to the values stored in the ASS header string, we need a wrapper class named AssStyles which is a container of AssStyle objects.


Implementation Tips

1. styles = AssStyles(GetVal(val_AssHeader)), the constructor extracts the information in the ASS Header string and store them in the AssStyles class instance.
2. The AssStyles class has a dict to hold the AssStyle objects, style = styles['style_name']
3. we can then access to the style values by style.name, style.fs, etc.