Merge pull request #232 from maxkorz/fix-rxjs

Don't import entire rxjs/Rx

Author: softsimon

src/dropdown/dropdown.component.ts

@@ -22,7 +22,8 @@ import {
   SimpleChanges,
 } from '@angular/core';
 import { AbstractControl, ControlValueAccessor, FormBuilder, NG_VALUE_ACCESSOR, Validator, FormControl } from '@angular/forms';
-import { Subject } from 'rxjs/Rx';
+import { Subject } from 'rxjs/Subject';
+import 'rxjs/add/operator/takeUntil';
 
 const MULTISELECT_VALUE_ACCESSOR: any = {
   provide: NG_VALUE_ACCESSOR,