Caption v1.3.0

Improvements

• Updated Electron.
• Better nothing found state.
• Better feedback when updating the app.
• Better loading state that works with multiple subtitle sources.
• If there are no subtitles found in a different language than English a popup appears.
• Does not find all subtitles #22 (will support more subtitle sources in the near future).

Fixes

• Better packager flow.
• MenuItem links to Electron links #30.
• Fix listItem icon (white when selected).