- Add support for jisho.org

- Update manifest.json to indicate support for Firefox on Android

- Fixed higher resolution icons

- Updated to use browser action (toolbar button) icon instead of badge text to convey Ruby Switch status
- Fixed application state after "Missing host permission for the tab" exception when calling insertCSS function after page loads but user has not clicked on Ruby Switch: "Permission needed"
- Installation of Ruby Switch adds browser action directly to toolbar