Method find, create and delete of the DocumentManager implemented.
Throw an UndefinedDocumentClassException if the target class is not defined.
DocumentManagerInterface updated.

The DocumentManager does not need anymore a property to store the target document class.
The document class is provided to the method find().
The DocumentFactory and the UndefinedDocumentClassException are now useless, so they have been removed.
Renaming of BadRevisionException to InvalidRevisionFormatException.

For greatest consistency with the HTTP response of CouchDB.
Add new RevisionInCreationException.

This exception is thrown when the user tries to create a document with an already defined revision.
Method update of DocumentManager implemented.
Move the Configuration class from the namespace Connector to Transport.
Improve documentation of the interfaces.
Update implementation of the delete and update methods of DocumentManager.

These methods now throw the exceptions defined in the interface.