Add support for complex objects

1) Exposed the emulation map so that custom constructors can be added to the unpickle function.
2) Added commands:
    * BINGET – read an object placed in a memo and pushed to the stack
    * OBJ – create a new class instance using the custom constructor and then applying the properties between that object on the stack and the marker
    * BUILD – Update an object instance with a dictionary of properties.
3) Added automated tests, as well as a helper python script to generate the appropriate pickle data.

Signed-off-by: Ian Reinhart Geiser <geiseri@yahoo.com>
Merge branch 'master' of https://github.com/geiseri/node-jpickle