Playback resuming enabled

New button for playing back videos at given timestamps given by an
additional t=TIME in the URL of webpage.
Multiple Video Support Enabled

Playback resuming and pausing should now have multiple video support,
with the exception of websites such as cs50.harvard.edu that don't allow
extraneous URL arguments
Experimental Code

Experimented with attempting to replace JWPlayer with HTML5 player
manually, without the need for CS50 2X. As of now this does not work and
is commented out; however if it could be made to work it would be a
significant improvement.
Notepad now opens in new window

- Notepad option now creates a new window rather than tab
- Notepad window now resizes nicely on open
- Regression: no longer able to load new_user.html on new detected
localStorage
Added additional documentation

Added comments above certain functions and subfunctions to clarify their
meaning in life.
Merge remote-tracking branch 'origin/pause-video'
Merge remote-tracking branch 'origin/application-combined'