FIP-0086 Include message-rebroadcast and skipping rounds (#998)

* Include message-rebroadcast and skipping rounds

* Typo

* Bit of text

* Fix line numbering

* Fix typo and line numbering again

* Fix comment

* Fix comment

* Update FIPS/fip-0086.md

Co-authored-by: Masih H. Derkani <m@derkani.org>

* Update FIPS/fip-0086.md

Co-authored-by: Masih H. Derkani <m@derkani.org>

* Update FIPS/fip-0086.md

Co-authored-by: Masih H. Derkani <m@derkani.org>

* Fix indenting

* Update FIPS/fip-0086.md

Co-authored-by: Alex North <445306+anorth@users.noreply.github.com>

* introduce backOffExponent

* Update COMMIT unblocking rule

* flip if statements

* Fix bug in DECIDE message validation

* Update Power(M)>2/3 to IsStrongQuorum

* Latest changes discussed in sync

* Update fip-0086.md

* addressed anorth's #998 (review) and fixed indentation to 2 spaces

* addresses #998 (comment)

* Fix reference to line number for `Valid` predicate

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Co-authored-by: Masih H. Derkani <m@derkani.org>
Co-authored-by: Alex North <445306+anorth@users.noreply.github.com>
Co-authored-by: vukolic <marko.vukolic@protocol.ai>