Media key support (#294)

* Introduce type for KeystrokeAction

* Increment dataModelVersion

New property 'type' for KeystrokeAction

* Mapping for media keys

* Media key selecting support for KeypressTab

* refactor: Use more meaningful name (selectedScancodeOption)

* Store the keystroke type in key action type instead of a new field

shared/src/components/popover/tab/keypress/keypress-tab.component.html

@@ -2,7 +2,7 @@
     <b class="setting-label">Scancode:</b>
     <select2
             [data]="scanCodeGroups"
-            [value]="scanCode.toString()"
+            [value]="selectedScancodeOption.id"
             (valueChanged)="onScancodeChange($event)"
             [width]="200"
             [options]="options"
@@ -47,4 +47,4 @@
     <i class="fa fa-info-circle"></i>
     When a key is configured as layer switcher key, you can't assign other functions to it.
     To assign a scancode to the key, set the <em>Layer action</em> to <em>None</em>.
-</div>
+</div>