client: rework page title

Remove "prototype" from the page title. Change the static <title>
to "StrongLoop Studio".

Modify the generated `version.js`:
 - dynamically set document.title to "StrongLoop Studio Beta"
 - make the name displayed in the page consistent with the
   document.title, e.g. "StrongLoop Studio Beta 0.2.0"
Merge pull request #394 from strongloop/feature/fix-page-title

client: rework page title
refactor studio and composer into modules
- fix unit tests
- change Profile to User module
- adjusted the request interceptors for Studio and Composer
-- studio does auth checking
-- Composer does error checking