Implement search and document view in webapp

Web interface for search and document details has been implemented by using
angular.js and bootstrap. A couple of controllers, templates and stylesheets,
nothing interesting there.

JavaScriptRouterController has been removed, because it causes a lot more
headaches than it solves, and code is a lot cleaner and easier to manage when
not fully coupling client code (JavaScript) and server code (Scala). With that
previous "jsRoutes" approach, instead of simply sending HTTP requests and
receiving responses to the API routes of server, we would use intermediate
objects mapping those routes, but they will expose (and require to use) some
implementation details of the Scala code (mainly: package and name of
controllers), which is totally insane: I want my client code to me as much as
decoupled from my server code as It can.

Some bugs in Searcher and some improvements (added cached responses for
documents) have been also made.