allow read/put use at module level

Not exactly sure, why I decided using "del" wouldn't be good
enough, but having the option of an easier interface is no bad thing.

It is an open question if we should allow read/put on module and on
class level or hide the class methods.

Re-using the same class for multiple put()s is in theory faster, but not sure if that is relevant with the overhead the binding introduces.
Even when we decide to hide read/put on class level, we might just keep them for now, mark them as deprecated and remove them from documentation.