Merge remote-tracking branch 'origin/master'

Allowed for 24 hour time periods in app preferences, upgraded wrapper.

Google Play link.

Deps, wrapper, tools update.

Target and compile for latest platform.

Stop ProGuard from minifying files causing issues.

Change Gradle wrapper.

Update .gitignore, add in signing setup.

Update README.

Cleaned up the UI a little, added app icons to list view - optimised …

…scrolling significantly.

Restore old LE params after write.