Factorize LHS of rules
Much better match-side factorization
Also factorize empty list tail
Factorize nested constructors in builds
More reuse in the factorization for match
Factorize for builds in premises.
Cleanup
Factorization. Redone.
Fallback case
Simplify factorization for LHS and RHS
Simplify factorization of source and target components
Some factorization of relations in premises
Properly factorize the rhs of relation premises
Separate variable reference marking from desugaring.
Merge branch 'master' into redo-factorization

* master:
  Convert to Maven project.
  Removing references to the coq definition file.
Cleanup