v2.0.0

Breaking Configuration Changes

• The base_layer must be specified in the configuration (it is not inferred automatically anymore).
• Split layer_lock target into separate layer and lock targets.
• Locked layers no longer automatically have temporary modifiers to revert their activation.
  Temporary modifiers can be specified with the layer target like normal modifiers.

Code changes

• Improvements to the tray icon code: Message loop and window creation handled by the winmsg-executor crate.
• Use stabilized language and library features: C-String literals and TLS functions
• Better handling and documentation around re-entrancy of the low level keyboard hook
• Refactor layout handling:
  • Remove manual bit packed keymapping representation
  • Prepare for layouts to be serialized
  • Clear interface between immutable layout and virtual keyboard using the layout
  • Remove all graph algorithms and dependency on petgraph