v0.3.0 - Backup & Restore

New features:

• Backup & Restore implemented and can be found in the settings.
• Linux support added.

Slight data overhaul:

• History is now stored in json instead of csv, automatic conversion will be applied when the app is first launched.
• History version property removed due to redundancy.
• version.txt files are now automatically created for all accounts for easy data conversion updates.