Reverted the ngx-dnd back to 3.1.0

+ Added missing debounceTime imports to prevent errors

src/app/main/content/apps/chat/sidenavs/left/user/user.component.ts

@@ -1,6 +1,7 @@
 import { Component, OnDestroy, OnInit } from '@angular/core';
 import { ChatService } from '../../../chat.service';
 import { FormControl, FormGroup } from '@angular/forms';
+import 'rxjs/add/operator/debounceTime';
 import 'rxjs/add/operator/distinctUntilChanged';
 
 @Component({

src/app/main/content/apps/contacts/contacts.component.ts

@@ -4,6 +4,7 @@ import { fuseAnimations } from '../../../../core/animations';
 import { FormControl, FormGroup } from '@angular/forms';
 import { FuseContactsContactFormDialogComponent } from './contact-form/contact-form.component';
 import { MatDialog } from '@angular/material';
+import 'rxjs/add/operator/debounceTime';
 import 'rxjs/add/operator/distinctUntilChanged';
 import { Subscription } from 'rxjs/Subscription';
 

src/app/main/content/apps/todo/todo-details/todo-details.component.ts

@@ -5,6 +5,7 @@ import { Subscription } from 'rxjs/Subscription';
 import { FormBuilder, FormGroup } from '@angular/forms';
 import { FuseUtils } from '../../../../../core/fuseUtils';
 import { fuseAnimations } from '../../../../../core/animations';
+import 'rxjs/add/operator/debounceTime';
 import 'rxjs/add/operator/distinctUntilChanged';
 
 @Component({

src/app/main/content/apps/todo/todo.component.ts

@@ -4,6 +4,7 @@ import { TodoService } from './todo.service';
 import { FormControl } from '@angular/forms';
 import { Todo } from './todo.model';
 import { fuseAnimations } from '../../../../core/animations';
+import 'rxjs/add/operator/debounceTime';
 import 'rxjs/add/operator/distinctUntilChanged';
 
 @Component({

src/app/main/content/pages/faq/faq.component.ts

@@ -3,6 +3,7 @@ import { FormControl } from '@angular/forms';
 import { Subscription } from 'rxjs/Subscription';
 import { FaqService } from './faq.service';
 import { FuseUtils } from '../../../../core/fuseUtils';
+import 'rxjs/add/operator/debounceTime';
 import 'rxjs/add/operator/distinctUntilChanged';
 
 @Component({