Eximchain Integration - Gas Price

[Lsquared13]

Issue

We need to turn gas price back on since Eximchain is a public network. We also need to determine what to do about validator gas, integrate any changes related to that, and test the whole thing.

Progress So Far

@andreweximchain has done the initial work for this on the eximchain-integration branch

Acceptance Criteria

• We have determined what we will do about validator gas and integrated any related changes
• We have tested the gas price changes on a test network and confirmed the network still runs with gas on.