Inferno v1.6.6

Update v1.6.4.0 release notes

Updated release notes for v1.6.3.0.

Micro-optimization.

Cleanup.

Improvement to B64Extension.ToB64Url (handling of zero-length arrays/…

…segments).

Small optimization.

Improvements and bug fixes after a personal code review, as well as i…

…ndependent professional audit (Cure53 team).

-AesCtrCryptoTransform improvements.
-CryptoRandom bug fixes.
  "NextDouble()" now generates 52 bits of entropy.
  "NextBytes()" is rewritten to avoid a possible serious concurrency flaw.
-Minor improvements and fixes throughout the codebase.
-Version bump to 1.4.

Small tweak to CryptoRandom's SanityCheck.

Version bump to 1.2.1.