Rewriter v0.0.7

A pre-release tag for use with Fiat Cryptography v0.0.16 and a non-dev opam package.

What's Changed

• Cache reified lemmas with LetIn by @JasonGross in #77
• Next batch of Ltac2 reification attempted performance improvements / experiments by @JasonGross in #67
• Add debug profiling to _Reify_rhs by @JasonGross in #68
• Don't duplicate reification typechecking time in Qed by @JasonGross in #69
• Remove dead code by @JasonGross in #70
• Don't allocate an unchecked evar for identifier types by @JasonGross in #71
• Add UnderLetsCacheProofs for better Reify_rhs proofs by @JasonGross in #72
• Control.once in debug_profile by @JasonGross in #76
• Global Strategy -1000 [UnderLets.to_expr]. by @JasonGross in #75
• Route through _Reify_rhs for all rewriting by @JasonGross in #73
• Add some Ltac2 util by @JasonGross in #78
• reify_in_context_opt now returns reified types too by @JasonGross in #74
• Use to_expr_App instead of to_expr so that reduction works correctly by @JasonGross in #79

Full Changelog: v0.0.6...v0.0.7