Added back old method of getting caption position for Flash video playback.
Added back old method of getting caption position for Flash video playback.

Because with speed changing the time also changes for Flash playback,
a different way to calculate the current time is needed than for HTML5
playback. I have added conditions for Flash and HTML5 video, and put
old method of calculating time for Flash.

I have tested it on the YouTube video ZwkTiUPN0mg. Both HTML5 mode and
Flash mode have proper video-captions syncing with this fix. NOTE: to view
YouTube video in Flash mode you either have to use an old browser (ex. Firefox
version 18) or hard code in source that state.currentPlayerMode = 'flash' (in
function _setPlayerMode(), file 01_initialize.js).

bmedx/modulestore,bmedx/modulestore,bmedx/modulestore