Finish up initial trimming changes.
Trim off more unneeded parts.
Finish initial line munging changes.

This function is still completely terrible and should probably be split
into several sub-functions.

I will probably introduce a line class that abstracts some of the
jankiness.

Specific changes include:
- Support for more styles of the transform tag.
- Support for multiple clips in a line.
- Actually pass the variables functions need to them, except for the
options table.
- Not actually better handling of \fad(e). Yet.
Move even more things out Aegisub-motion.moon