Merge branch 'dmdimitrov/query-builder-improvements' of https://github.com/IgniteUI/igniteui-angular into dmdimitrov/query-builder-improvements

Author: gedinakova

projects/igniteui-angular/src/lib/query-builder/query-builder-tree.component.ts

@@ -6,7 +6,7 @@ import {
     Output,
     TemplateRef
 } from '@angular/core';
-import { getLocaleFirstDayOfWeek, NgIf, NgFor, NgTemplateOutlet, NgClass, DatePipe } from '@angular/common';
+import { getLocaleFirstDayOfWeek, NgTemplateOutlet, NgClass, DatePipe } from '@angular/common';
 import { Inject } from '@angular/core';
 import {
     Component, Input, ViewChild, ChangeDetectorRef, ViewChildren, QueryList, ElementRef, OnDestroy, HostBinding