#814 fix MDL issues

- additional workarounds for Material Design Lite problems
- validation fixes

fixes #814

ng2-components/ng2-activiti-form/src/components/widgets/functional-group/functional-group.widget.ts

@@ -15,7 +15,7 @@
  * limitations under the License.
  */
 
-import { Component, OnInit } from '@angular/core';
+import { Component, OnInit, ElementRef } from '@angular/core';
 import { WidgetComponent } from './../widget.component';
 import { FormService } from '../../../services/form.service';
 import { GroupModel } from './../core/group.model';
@@ -36,7 +36,8 @@ export class FunctionalGroupWidget extends WidgetComponent implements OnInit {
     minTermLength: number = 1;
     groupId: string;
 
-    constructor(private formService: FormService) {
+    constructor(private formService: FormService,
+                private elementRef: ElementRef) {
         super();
     }
 
@@ -108,4 +109,19 @@ export class FunctionalGroupWidget extends WidgetComponent implements OnInit {
             event.preventDefault();
         }
     }
+
+    setupMaterialComponents(handler: any): boolean {
+        // workaround for MDL issues with dynamic components
+        if (handler) {
+            handler.upgradeAllRegistered();
+            if (this.elementRef && this.value) {
+                let container = this.elementRef.nativeElement.querySelector('.mdl-textfield');
+                if (container) {
+                    container.MaterialTextfield.change(this.value);
+                }
+            }
+            return true;
+        }
+        return false;
+    }
 }