Factoring constraints into a separate file.
Working on constraint equivalence.
Working on constrained declarations.
Merge branch 'constr' of github.com:cplusplus/concepts-ts into constr
Define constraint equivalence.
Rewording subsumption.
Rework constraint expressions, normalization.
Working on normalization.

- Require that concept inlining occur before further
  normalizing subexpressions.
Define universally quantified constraints.
Merge branch 'constr'

Conflicts:
	src/templates.tex
[intro] Update references.
[expr] Update references.
[dcl.dcl] Update references.
[dcl.spec.constr] Wording change.
[dcl.spec.auto] Fix wording.

- Make the note in p2 normative, and clean up the wording.
[dcl.spec.auto] Update section headings.

- Document rationale for changes to this section.
[temp.constr.decl] Update references.
[intro] Update references.
[dcl.spec.auto.constr] Rewrite association paragraph.
[dcl.spec.concept] Update references.