* [DEV-312] Take in account subnetwork's GAS limit, when adding
transactions to block. Try to do that optimally.
* [DEV-312] Fixed GAS overusage calculation
* [DEV-337] Make sure that a transaction that uses more gas than the total allowed for sub-network
* [DEV-337] Moved transaction GAS check to mempool
* [DEV-337] Added Unit test for gas usage in transaction
* [DEV-337] Fixed build
* [DEV-337] Fixed tests stuff
* [DEV-337] Removed TODO comment
* [DEV-303] Implement block finality
* [DEV-303] Add finality tests
* [DEV-303] Make finality tests use maybeAcceptBlock
* [DEV-303] Only check finality rules if we are fastAdd mode
* [DEV-303] replace hasBiggerFinalityScoreThan checks with .finalityScore()
* [DEV-308] Enforce tx order in block to be by sub-network ID
* [DEV-308] Use mutable block in TestCheckBlockSanity
* [DEV-308] Fixed comment
* [DEV-308] Fixed TestCheckBlockSanity: use invalid block instead of modifying good block
* [DEV-308] Changed name of block in TestCheckBlockSanity
* [DEV-255] create checkConnectToPastUTXO and move the required functionalities to it from checkConnectBlock
* [DEV-255] get rid of checkConnectBlock
* [DEV-255] rename pNode -> node
* [DEV-255] add comment to describe ErrWithDiff