* Remove As usage from CHT

* Remove As usage from CHT (continue)

* Restrict BN <-> int conversions in CT

* more BN <-> u64 conversions removed

* upd spec_version

* Apply suggestions from code review

Co-Authored-By: Gavin Wood <[email protected]>

* Apply suggestions from code review

Co-Authored-By: Gavin Wood <[email protected]>

* more grumbles

* fix last grumbles + compilation

* too long lines

* too long lines