Refactored most of the codebase

• Restructured the project to make it easier to maintain and extend #49
• Improved the accuracy for the remaining_time, progress and eta placeholders #43
• Renamed the notification placeholder remaining -> remaining_avg
• Added new custom notification placeholders: remaining_file, remaining_filament, remaining_slicer, cur_layer, max_layer
• Added the ability to use custom_notifcations via a custom macro. See Custom Notification documentation.

Related fixes:

• Error transitions only trigger notifications during printing #46

Custom Notifications

• Added support for custom notifications via the M117 command
• Log location is now moved to klipper logs dir, please run ~/mobileraker_companion/scripts/fix-log-location.sh on existing installations to ensure it works.

0.2.1

• Added support for multiple printers using a single companion instance
• Added support for trusted clients using the API key of moonraker

Beta testing

Beta version.