add-mockup-controller and use saas-bootstrap

In this PR:
1.I found there was a "bootstrap/examples" folder in the views including some html pages. I assume these files are sort of html mockup files. If so, it would be better we create a mockup controller and then put all these files into corresponding views folder. The project will be more organised.


2.I also noticed bootstrap files were manually put into assets. So I add gem "bootstrap-sass" and customise bootstrap css and javascripts to be loaded. When the Twitter Bootstrap is updated, "bootstrap-saas" will take charge of updating the saas version. What we only need to is to update the gem version.


Suggestions:
Since this is a web app, functionalities specification(can be in the "issues") and testing codes is necessary, which will make the project more maintainable and in the control with the growth of developments. Also, as I said before, it would be easier for more people involved in the project.