* Implement StringFactory on the companion object for BtcHumanReadablePart
* Make Bech32.checkHrpvalidity() take in a string rather than a Bech32HumanReadablePart as a parameter, now we check validity _just_ according to the bech32 standard, not specific applications light lightning / bitcoin
* Add missing override
* Overload Bech32.checkHrpValidity() to pass in a 'StringFactory' in cases where you know what HRP you expect
* Do nadav's suggestion on Bech32.splitToHrpAndData() -- allow a factory to be passed in parameterized with the type you expect
* Introduce 'FilterSyncMarker' to ChainApi, make it clearier what exactly the (Int,DoubleSha256Digest) tuple is returned from ChainApi.nextBlockHeaderRange()
* Fix doc
* Add scaladoc to FilterSyncMarker
* Rebase onto master, fix conflicts to use FilterSyncMarker
* Pull over test cases, WIP
* Rework ChainHandler.nextBlockHeaderRange() to use hashes rather than heights to very integrity of header chain, add test case
* Modify test case to make sure we are generating the 'heaviest chain work' header as first in the tuple that is used in reorg test cases
* Refactor to helper method called 'findNextHeader()' to make things simpler
* Add scaladoc to ChainHandler.findNextHeader()
* WIP
* Fix bugs in ChainApi.nextBlockHeaderRange(), now return (startHeight,stopHash) rather than (stopHeight,stopHash)
* Get chain handler tests passing, remove genesis filter header/fitler from default chain project fixture, make it a specialized one to have genesis filter header/filter in the database. Use that specialized fixture in ChainHandlerTest for now
* FilterSync work without having the genesis filter and filter header inserted into the database
* fix bug in DataMessageHandler where we were using sendNextGetCompactFilterHeadersCommand rather than using peerMsgSender.sendGetCompactFilterHeadersMessage
* Refactor ChainHandler.findNextHeader() to centralize where chains are fetched
* Address ben's code review
* Create FeeUnitFactory and functions to calculate tx fee rates
* Remove useless override, use factory
* doc
* Scaladocs + use vals
* Fix scaleFactor being set as default value
* Fix maxBy() exception in the case of empty Blockchain in ChainHandler.bestFilterHeaderSearch()
* Add another unit test to CompactFilterHeaderDAO for coverage
* Implement getBestFilterHeader based on a number of block headers that can be passed in as a parameter. These headers can be used to indicate what your current best chain is
* Bring back compiler opts
* Fix compiler error for maxByOption as it isn't in the 2.12 std library
* Implement a context free best filter headers search. The basic strategy is to look at headers in the _future_ of our current best filter header
* Fix bug in sql query were we were doing max chainWork too early on block headers, we needed to filter out headers in our set and _then_ we get the max chain work
* Add more unit tests
