Reorganizing TextTrack code.
Remove focus from other elements on click.
Capture all key events in the editor.
Fix audio-from-URL menu item.
Fix segment-deletion bug
Fix Time Shift Tool

Also fix corruption in MP3 codec.
Added file drag-and-drop
Added click-and-drag multiselect.
Fixed typo in Match Repeat code
Add Drag-and-Drop Audio
Drag-and-Drop Audio URLs
Made the timeline emit a cuechange event when the text is updated.
Merge remote-tracking branch 'origin/master'
Inline waveform worker script.
Efficiency Improvements

Moved resampling to a Worker and reduced re-renders with
requestAnimationFrame.
Improve Zoom Menu Options
Minor bugfixes.
Eliminate redundant checks for image availability.
Finished new selection tool.
Sync with changes to Renderer interface

Also added a new menu option.