message: add openDrawer and openDrawerOnSmallScreens method on mdl-layout
diff: @@ -286,6 +286,13 @@ export class MdlLayoutComponent implements AfterContentInit, OnDestroy, OnChange
  }
  }
  + public openDrawer() {
  + this.isDrawerVisible = true;
  + if (this.drawer) {
  + this.setDrawerVisible(true);
  + }
  + }
  +
  private setDrawerVisible(visible: boolean){
  this.drawer.isDrawerVisible = visible;
  this.drawer.isDrawerVisible ? this.onOpen.emit() : this.onClose.emit();
  @@ -332,6 +339,12 @@ export class MdlLayoutComponent implements AfterContentInit, OnDestroy, OnChange
  }
  }
  + public openDrawerOnSmallScreens() {
  + if (this.isSmallScreen && !this.isDrawerVisible) {
  + this.openDrawer();
  + }
  + }
  +
  public hasDrawer() {
  return !!this.drawer;
  }
  