Delete the old implementations of the CFG, CDG, DomTree, and dataflow
Finish implementing the controlDependencies accessor
Use the HasBlockReturns class in the accessors for that analysis
Rename mkCFG -> controlFlowGraph

This is more consistent with the rest of the data type constructors in
the rest of the library.
Combine the implementations of the call graph and its traversal

The traversal depends on some details from the call graph, but I
didn't want to expose those details to users as a stable interface.
The details are available through the Internal module, which is not
going to be stable.

The public interface modules re-export the appropriate functions
and types.
Explicitly export the CallGraph.Internal module
Documentation for Dominators
Do not export an unused type alias in the NoReturns analysis
Major version bump due to all of these changes

Assuming we keep this branch
Update tests to minor API changes
Cabal file cleanup

Now dependencies with version bounds are on their own
line so that changes cause less git diff churn