add done text property

Author: Christian Mayr

nativescript-imagepicker/index.d.ts

@@ -80,6 +80,8 @@ interface Options {
      */
     mode?: string;
 
+    doneText?: string;
+
     android?: {
         /**
          * Provide a reason for permission request to access external storage on api levels above 23.

nativescript-imagepicker/viewmodel.ios.ts

@@ -70,7 +70,7 @@ export class ImagePicker extends data_observable.Observable {
     }
 
     get doneText(): string {
-        return "Done";
+        return this._options && this._options.doneText ? this._options.doneText : "Done";
     }
 
     get cancelText(): string {