assert Node uid is of type uuid.UUID
clean up node.__cmp__
make Container inherit from DiGraph
delete first swath of unnecessary fxns for Container
don't need nodes property -- DiGraph has it
add placeholder class
fix namespace conflict with naming Relationals
fix error creating uuid4
move uniquify to the top
fix namespace error with Node
container is DiGraph, not a wrapper for one
nodes have node_name, not name
call Digraph initialization inside container
re add add_node_child/parent to Node class
add framework for new query engine
fix search functionality for names
start unifying the query interface to the objects
relink all gis objects on start of engine, fix interface to querying names
implement search for uuid
implement variables in query language