Docs updated to v0.4.0
Update to v0.4.0
Major overhaul of the Syringe object definition

Syringe has been refactored to make its public methods part of the
object prototype. The Syringe object class is now held inside a closure
and can be re-used by all newly create Syringe object instances. This
leads to performance benefits and more efficient use of memory.

In order to keep the registry object inside the same closure (but not
have it clobbered every time a new Syringe object is created) the
registry is now compartmentalized by object ID.