Create shortcutmanager class and move shortcuts in the tools themselves

[pieterdeschepper]

Shortcuts & Tools Panel

• Shortcuts attached directly to the tools
• Support for mac (Meta key instead of CTRL)
• Show the shortcut keys in the UI
• Made the toolsPanel more dynamic, move the tools configs to its own classes

Some small UX stuff:

• Make sure you can scroll the layer panel when there are a lot of layers
• Contributors list is static, will scroll on hover

[gniziemazity]

Really nice updates :-) Thanks for contributing!