* only register keyboard bindings that are backed by actual
editor actions
* rename BpmnKeyBindings -> BpmnKeyboardBindings for parity with
diagram-js@latest
* sub-class and override _keyboardBindings_ service provided
by diagram-js
* extend spec to verify default actions
* use ES6 import / export
* UTILS: export individual utilities
* TESTS: localize TestHelper includes
BREAKING CHANGE:
* all utilities export independent functions
* library sources got ported to ES6. You must now use
a ES module bundler such as Browserify + babelify or
Webpack to consume this library (or parts of it).