Use Django {% url %} and RequestContexts

Use some good Django's practices
- Allow for different urls/roots by using {% url %} template syntax (no more hardcoding urls)
- Allow use contexts and (and therefore RequestContexts)
 --- which allows setting of 'content' (static JS/CSS) to be delivered from a different URL
- fix a "dashboard" Json error when the URL had a proper dashboard name (data needed to be Json decoded) 
- add the needed pickle objects (issue #608)