Video Sync is Broken

[gr812b]

Feature Description
Bring back video sync! Its not too broken, just needs linking up again with some basic stuff. I think the backend shouldnt need any changes and the front end should just work by looking at the global file information stored rather than requesting it each time. Try to merge it nicely with the new stuff please rather than making old code goopily work. :D

[gr812b]

#260 Related!

[gr812b]

The logic for writing the lines on the front end should work well still too, and I believe I already updated most of it to use the fileContext stuff, so not far!