Pause video when showing modal dialogs
Added dialog to save subtitles on resume session errors (#1302)

Added a new dialog for resume session errors.  It shares the same
scope with the save session error dialog (i.e. it's controlled by
SaveErrorModalController)

Removed extra </div> in the save error dialog.

Added button to show the dialog in the debug window

Changed secondsUntilClosing back to 120.  I messed with it for my last
commit.
Better UI when tasks can't be approved.

Made it so the style for a disabled approve button works (before it
was being overridden by other CSS classes).  Changed it so that we
display a pointer over the approve/send-back buttons if they're not disabled.

Changed the text for the error messages when subtitles aren't
complete.  Added a right margin to the text.