Convert errors in Silex to JSON responses
Stubbed storage
Switched to a SF2 DIC base
Removed silex

Very "funny" side effects with shared objects between instances during
test runs. Annoying.
Added: Dependencies on pure SF2 components
Added: New SF2 based endpoint
Use SF2 application during tests
Added: New DIC XML config
Set proper request context
Removed comment
Clone request in tests

This clone is ESSENTIAL. Symfony2 stores the matched controller inside
the request. Since we are replaying the requests from the first test in
the second tests and this uses the same request object, the route would
not be matched again. This causes the cotnroller from the first test run
being re-used, which also means that the first few requests run against
the storage from the first run.
Removed debug code
Implemented: Store and count documents
Stubbed update sequence calculation

We should find out what would be really correct here, accoring to the
CouchDB semantics. This works for now.
Stubbed: Return changes feed

Right now it ignores the since parameter, but this is TDD…
Implemented: Retrieve document from database
Implemented: Return requested document in multipart mime response