+ decentralized shortcut declaration
+ each service/controller is now responsible for declaring its shorcuts
- documentation (cheatsheet) is still to be maintained manually
- init order matters (shortcutService has to be instanciated before
everyone else) => should have a standalone KeyboardService singleton
which is ready as soon as it is loaded
+ added shortcuts for all tools in ToolController
+ modified structure of tools in Controller to Array of descriptors to
allow to declare shortcuts directly when setting up the tool controller
+ moved keycode translation to KeycodeTranslator
+ made KeycodeTranslator more generic to handle 0-9 and a-z keys
+ small refactor in KeyboardEventService
