Collection navigation implemented

When user creates a collection of resources for any node, those collection objects detail view is getting displayed and navigated on the same page using an ajax call.
Now according to this for every click on collection node it doesn't loads the entire page as it was previously.

Modification in :
```
groupDashboard.html
image_detail.html
page_details.html
quiz_create_edit.html
quiz_details.html
quiz_item_create_edit.html
quiz_item_details.html
video_detail.html
```
For above files common url is made for editing the node in node_ajax_view.html which is included in node_details_base.html which is again extended by all above templates.

```
node_details_base.html
```
Script written for navigation of collection node using an ajax call.

```
node_ajax_view.html
```
Added new template which handles the node details part (body-content) on ajax call on same page.
Which also handles the edit-url from tag according to the type of resource selected.

```
ndf_tags.py
```
Added "get_edit_url()" tag which detects the type of resource according to selected resource and returns the appropriate url.

```
urls/quiz.py
```
Accordingly updated urls to create and edit quiz-node

```
ajax_views.py
```
Added "collection_nav()" function to handle the ajax call for navigation of collection.