fix method name

Author: parveshneedhoo

www/imagepicker.js

@@ -32,7 +32,7 @@ ImagePicker.prototype.requestReadPermission = function(callback, failureCallback
   return cordova.exec(callback, failureCallback, "ImagePicker", "requestReadPermission", []);
 };
 
-ImagePicker.prototype.forceClose = function(callback) {
+ImagePicker.prototype.closeImagePicker = function(callback) {
   return cordova.exec(callback, null, "ImagePicker", "closeImagePicker", []);
 };