Remove debugging printout statements / update some comments
Revert "Made eqTyCon to be heterogeneous."

This reverts commit 9fe478d5b6c683ebb12d52696c7fb0eb81ad51d0.

Conflicts:

	compiler/deSugar/DsBinds.lhs
	compiler/typecheck/TcHsType.lhs
	compiler/typecheck/TcMType.lhs
	compiler/types/Coercion.lhs