Require envdir (to be used for upcoming changes in deployment mechanisms)
Highlight the currently-playing sentence during transcript audio playback.

- Gives each complete sentence an id of #s123 where 123 is the sentence ID.
- Backend embeds information about sentence start/stop times.
- Frontend scans sentence info during playback and updates highlights as needed.

Further work is to be done to improve performance of scanning sentences so we get closer to O(1) speed instead of the current O(n) speed.
Use more efficient lookup of which sentence is currently playing.

Also, use 'info' instead of 'active' to highlight current sentence (higher contrast, easier to see).
Highlight 'Read' in navbar when transcript is finished
Currently disabled: Jump to a sentence in the audio when its timecode is clicked

This is disabled right now because doing any sort of seeking within audio is very inaccurate if the audio is not in a format that Flash is expecting.
Do not update page title while audio is playing