* [NOD-641] Upgrade to github.com/pkg/errors v0.9.1 and use errors.As where needed
* [NOD-641] Fix find and replace error
* [NOD-641] Use errors.As for error type checking
* [NOD-641] Fix errors.As for pointer types
* [NOD-641] Use errors.As where needed
* [NOD-641] Rename rErr->ruleErr
* [NOD-641] Rename derr->dbErr
* [NOD-641] e->flagsErr where necessary
* [NOD-641] change jerr to more appropriate name
* [NOD-641] Rename cerr->bdRuleErr
* [NOD-641] Rename serr->scriptErr
* [NOD-641] Use errors.Is instead of testutil.AreErrorsEqual in TestNewHashFromStr
* [NOD-641] Rename bdRuleErr->dagRuleErr
* [NOD-641] Rename mErr->msgErr
* [NOD-641] Rename dErr->deserializeErr
* [NOD-201] Implemented the AddSubnetwork CLI tool.
* [NOD-201] Fixed various bugs in AddSubnetwork.
* [NOD-201] Fixed mempool maybeAcceptTransaction verifying gasLimit for a subnetwork registry transaction.
* [NOD-201] Fixed serialization/deserialization bugs in addrIndex.
* [NOD-201] Fixed BlockConfirmationsByHash not handling the zeroHash.
* [NOD-201] Used btclog instead of go log.
* [NOD-201] Made gasLimit a command-line flag. Made waitForSubnetworkToBecomeAccepted only return an error.
* [NOD-201] Filtered out mempool transactions.
* [NOD-201] Fixed embarrassing typos.
* [NOD-201] Added subnetwork registry tx fee + appropriate cli flag.
* [NOD-201] Skipped TXOs that can't pay for registration.