This is a minimal set of changes to make things work with the new types
in nim-eth - this is the minimal PR that merely resolves
incompatibilities while the full change set would include more cleanup
and migration.
* remove some redundant EH
* avoid pessimising move (introduces a copy in this case!)
* shift less data around when reading era files (reduces stack usage)
Jacek Sieka
Advaita Saha