doc: add Hacking.md

This guide contains instructions on how to set up a basic development
environment for ZeroCloud using a virtual machine and DevStack.
README: add links to the detailed docs
Merge pull request #20 from larsbutler/hacking-guide

Add ZeroCloud "hacking" guide
add isinstance check to ObjPath equals operator

ObjPath class __eq__ and __ne__ operators were not checking that instance of the ObjPath class wass passed to them
Merge pull request #21 from pkit/minor_fixes

add isinstance check to ObjPath equals operator