Interface for Demos and a SVR Demo

1. Add a general urls.py rule. It will handle links like **shogun-toolbox.org/demos/demo-name/function** with *pages.views.demoHandler*. The mechanism of demoHandler is to
find the matching class in the demos.py by the demo-name specified in the link,
invoke the matching funtion. the function receives the request and
processes the request into the response and returns. The returned response
are sent to the page finally via the demoHandler. 
2. Add svr demo to the demos.py. 
3. add some js librarys for the demostration. 
4. don't know why shogun.sqlite is always commited, I'tried to git checkout to revert it, but no use indeed. just ignore it.