chore(keyboard): register keys backed by editor actions only

* 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

lib/features/keyboard/BpmnKeyboardBindings.js

@@ -0,0 +1,158 @@
+import inherits from 'inherits';
+
+import KeyboardBindings from 'diagram-js/lib/features/keyboard/KeyboardBindings';
+
+
+/**
+ * BPMN 2.0 specific keyboard bindings.
+ *
+ * @param {Injector} injector
+ */
+export default function BpmnKeyboardBindings(injector) {
+  injector.invoke(KeyboardBindings, this);
+}
+
+inherits(BpmnKeyboardBindings, KeyboardBindings);
+
+BpmnKeyboardBindings.$inject = [
+  'injector'
+];
+
+
+/**
+ * Register available keyboard bindings.
+ *
+ * @param {Keyboard} keyboard
+ * @param {EditorActions} editorActions
+ */
+BpmnKeyboardBindings.prototype.registerBindings = function(keyboard, editorActions) {
+
+  // inherit default bindings
+  KeyboardBindings.prototype.registerBindings.call(this, keyboard, editorActions);
+
+  /**
+   * Add keyboard binding if respective editor action
+   * is registered.
+   *
+   * @param {String} action name
+   * @param {Function} fn that implements the key binding
+   */
+  function addListener(action, fn) {
+
+    if (editorActions.isRegistered(action)) {
+      keyboard.addListener(fn);
+    }
+  }
+
+  // select all elements
+  // CTRL + A
+  addListener('selectElements', function(context) {
+
+    var event = context.event;
+
+    if (keyboard.isKey(['a', 'A'], event) && keyboard.isCmd(event)) {
+      editorActions.trigger('selectElements');
+
+      return true;
+    }
+  });
+
+  // search labels
+  // CTRL + F
+  addListener('find', function(context) {
+
+    var event = context.event;
+
+    if (keyboard.isKey(['f', 'F'], event) && keyboard.isCmd(event)) {
+      editorActions.trigger('find');
+
+      return true;
+    }
+  });
+
+  // activate space tool
+  // S
+  addListener('spaceTool', function(context) {
+
+    var event = context.event;
+
+    if (keyboard.hasModifier(event)) {
+      return;
+    }
+
+    if (keyboard.isKey(['s', 'S'], event)) {
+      editorActions.trigger('spaceTool');
+
+      return true;
+    }
+  });
+
+  // activate lasso tool
+  // L
+  addListener('lassoTool', function(context) {
+
+    var event = context.event;
+
+    if (keyboard.hasModifier(event)) {
+      return;
+    }
+
+    if (keyboard.isKey(['l', 'L'], event)) {
+      editorActions.trigger('lassoTool');
+
+      return true;
+    }
+  });
+
+  // activate hand tool
+  // H
+  addListener('handTool', function(context) {
+
+    var event = context.event;
+
+    if (keyboard.hasModifier(event)) {
+      return;
+    }
+
+    if (keyboard.isKey(['h', 'H'], event)) {
+      editorActions.trigger('handTool');
+
+      return true;
+    }
+  });
+
+  // activate global connect tool
+  // C
+  addListener('globalConnectTool', function(context) {
+
+    var event = context.event;
+
+    if (keyboard.hasModifier(event)) {
+      return;
+    }
+
+    if (keyboard.isKey(['c', 'C'], event)) {
+      editorActions.trigger('globalConnectTool');
+
+      return true;
+    }
+  });
+
+  // activate direct editing
+  // E
+  addListener('directEditing', function(context) {
+
+    var event = context.event;
+
+    if (keyboard.hasModifier(event)) {
+      return;
+    }
+
+    if (keyboard.isKey(['e', 'E'], event)) {
+      editorActions.trigger('directEditing');
+
+      return true;
+    }
+  });
+
+};