Make LineCollection not require a loaded video.

Additionally, add a validation callback that can be used to determine
if a line should be added to the collection or not.

If the validation function returns false, the line will not be added.
By default, only commented lines are ignored.

Also fixes a copy-paste coding bug.
fetchDataFromClipboard doesn't do any filtering.

Because it's allowed for people to paste filepaths instead of the
tracking data itself, filtering here doesn't make sense.
Add file opening and parsing.

Also, validate data in parseRawDataString.
Initialize parsed data tables in parse method.

Prevents them from being extended when data is re-parsed.
Use math.
Fix the transform stuff.

It actually works now.
Update dialog tables.
Overhaul prepareConfig.

Move things into place for clip tracking.
Convert clips with a scaling factor to floating-point coords.
Add extradata before the line text has been modified.

Duh.
Brutalize fad.

Turn them into transforms. This is still wrong in a bunch of edge
cases, but at least it's a lot less wrong than doing nothing.
Skip an extra index.
Put more effort into parsing initial clipboard data.
Do things in the correct order.
Start adding clip processing.