Abstract context-dependent block checking from acceptance
CreateNewBlock and miner_tests: Also check generated template is valid by CheckBlockHeader, ContextualCheckBlockHeader, CheckBlock, and ContextualCheckBlock
TestBlockValidity function for CBlock proposals (used by CreateNewBlock)
miner_tests: Disable checkpoints so they don't fail the subsidy-change test
Abstract DecodeHexBlk and BIP22ValidationResult functions out of submitblock
Implement BIP 23 Block Proposal
QA RPC tests: Add tests block block proposals
submitblock: Check for duplicate submissions explicitly