Set default time to 0
Add function to create a seed graph for BA mechanism
Add weighted seq creation function/tests
Add a function to pick random n unique elements
Change to random-m from random-n to be consistent
Add preliminary version of B-A graph creation
Change add-node and add-nodes to take graph and node(s) for simpler code
Make add-nodes use add-node so that add-node can check for undirectional
Move add-neighbors up so that it can be used by add-node

add-node uses add-neighbors to update the preexisting nodes' neighbors
Add add-node undirectional option that will update existing nodes
Change node addition to support undirectional add

Undirectiona add-node update existing nodes' neighbors
Add sampling package
Add undirectional B-A graph creation
Update edge extractors and tests
Add tests for edge counting in BA models
Update .gitignore