Add base graph assertion helpers
Use new graph assertions
Additional unit tests for cloning
Additional unit test for empty graph
Merge branch 'master' of https://github.com/clue/graph.git
Make number of vertices configurable
Update README to include more section headers
Update install instructions for GraphViz
Merge branch 'master' of https://github.com/clue/graph.git
Use subgraph clusters for vertex groups
Only add vertex labels when needed
Use php-cs-fixer to adopt PSR-2 code style
Add whitespace around operators
Remove trailing whitespace from each line
Consistently use single quotes
Add whitspace between concatenations
Align all comments consistently
Run php-cs-fixer once again
Merge branch 'graphviz-cluster'

Conflicts:
	lib/Fhaculty/Graph/GraphViz.php
Add skeleton for exporter/output