v0.8.0

Main changes:

• Explicitly state support for the Legion 5 (non pro)
• Better multithreading, should hang a whole lot less (at the cost of delays on updating the GUI)
• Reorganised the README, added preview image and a section about compiling from source

Other:

• Separated OS specific stuff
• General refactoring of GUI related code
• Updated dependecies
• Added keyboard_manager (future command line support preparations)