Issue #198: Refactor codebase organization to separate view from the mod
* backend code is now in the app folder
* cache folder now outside of web view too, in case we want to cache non-public data
* path to create a new views is now dispatcher -> (controller <-> model) -> view, the onestring view uses it
* other views not up to date work as before until they get ported to MVC
* web folder only contains front-end code now (that includes p12n and docs static folders)
* all traffic now goes through web/index.php, no need to specify the router script anymore with php dev server
* README updated