show static app

[felix-lambert]

This PR proposes to show the static apps and to resolve some exceptions linked to the behavior of an app without a server

[aenario]

Ok, one more round of changes :

• Please rename getUrlFor into getPathFor (url is in a network request, this is a path on the FS)
• Please try also with https://github.com/aenario/cozy-front-nopublic : http://my.cozycloud.cc/public/front-nopublic/ should get the <h1>Hello world</h1> page. (if there is no public folder, we consider its a single application serving both the public and internal role.)
• It's good to test manually, it's better to have travis testing for you Please add mocha tests with both tests repo.

Thanks !

[frankrousseau]

Do not forget to add tests.