Add first attempt at new DAG type
Add merging of non-Calc nodes, TGof, and TypeGuard merging tests. Fix mistaktes.
Add another DAG test
Parametrize Node in DAGs.jl on head
Add first attempt at PatternDAG, with more simplifications
Add a test for indirect merging of egal-classes and fix an oversight in substitute! to make it work
Pull out substitute_uses! from substitute!, and remove unwanted primary_rep
Reorder Use from (Int,Node) to (Node,Int)
Add some tests for more simplifications and fix them
Prioritize sources as primary reps
Pull PatternDAGs.jl out of DAGs.jl
Rename PatternDAG -> Graph to ease the transition
Adapt functinality from PatternGraphs into PatternDAGs, update exports
Adapt reemit and branch functionality from PatternGraphs into PatternDAGs
Use new DAGs instead of old ones
Remove old DAGs
Add test_dag.jl to runtests.jl
Replace remaining refsof -> usesof
Add moretests.jl with up-to-date, printing tests
Hack to make patterns with inverse functions nicer to read - shouldn't cause strange printouts in corner cases?