Runtime should verify read/write sets

[kostko]

The runtime should verify executed transactions against the received read/write sets. In case of mismatches the transaction should be reverted.

This should also implement the following storage helpers:

• A special ReadSyncer that intercepts storage reads and uses them to build/compare the read set.
• A MKVS write filter that can be used to easily build/compare the write set.

[kostko]

Reversion costing gas (see #2081 (comment)) requires the following things to be resolved first:

• Support special atomic storage operations on keys #1466 (and modifications in runtime-ethereum to use it) to avoid additional conflicts from being introduced.
• Transaction scheduler should use CheckTx #1963 (so that the transaction scheduler can make sure there will be enough balance to pay for gas even if the transaction is reverted due to an incorrect read/write set).