Update tslint to 4.x.x

Closes #166

src/components/popover/popover.component.ts

@@ -4,6 +4,7 @@ import {
 } from '@angular/core';
 
 import { Store } from '@ngrx/store';
+import { Observable } from 'rxjs/Observable';
 
 import {
     KeyAction,
@@ -19,7 +20,6 @@ import { Tab } from './tab/tab';
 
 import { AppState } from '../../store';
 import { getKeymapEntities } from '../../store/reducers';
-import { Observable } from 'rxjs/Observable';
 
 enum TabName {
     Keypress,

src/config-serializer/config-items/key-action/KeystrokeAction.ts

@@ -7,7 +7,7 @@ import { KeyAction, KeyActionId, keyActionType } from './KeyAction';
 export enum KeystrokeActionFlag {
     scancode = 1 << 0,
     modifierMask = 1 << 1,
-    longPressAction = 1 << 2,
+    longPressAction = 1 << 2
 }
 
 interface JsonObjectKeystrokeAction {