cleaned up predicate inheritance
reorganized and cleaned up policy inheritance
only do expensive topology equality check when necessary
minor refactor in runtime
improvements to std library
minor improvements to mac_learner
reactive compilation only happens after set_network is completed
Error handling of input and out-detection of pox install location
Removed redunandant NetworkDerivedPolicies and replaced w/ DyanmicPolicy implementation
rectified unimplemented predicate and policy __repr__
removed unneeded rule clearing in interpreted mode
fixed bug in which only the most recent parent received change notifications
overhaul/reorg of virtualization library
fixed bug in Port object equality testing
Major refactor of predicates and policies.

Now only DynamicPredicate and DynamicPolicy subclasses change.
Previous primitives with changing behavior such as flood, ingress_network
and egress_network are now subclasses of DynamicPredicate or DynamicPolicy.
The only exception being query policies which are their own thing for now.

Previous primitives such as move and modify have been subclassed from
DerivedPolicy as well, and semantics have been normalized (see changes to
examples).

A useful cross-forward DerivedPolicy has been added (semantically equivalent
to OpenFlow's fwd(port_num) action).
Added installation/setup instructions and link to video directory