Makes use of both bootstrap and a rendering of the Tracks logo to
provide a bit better experience in term of brand identity as well as
also supporting mobile better.
* scaffold.css is only used by login -> rename to login.css
* standard.html.erb is the default application layout -> rename to application.html.erb
* scaffold.html.erb is unused -> deleted
- adding missing Javascript includes
- fixing jquery for showing/hiding indentity url field
- adding identity url field to signup form
- fixing bug in signup controller