The goal of this commit is to fix loading blk*.dat files by BlockFileLoader. Bitcoinj cannot yet
create segwit transactions nor does it correctly process them.
Based on code by:
NicolasDorier <nicolas.dorier@gmail.com>
Oscar Guindzberg <oscar.guindzberg@gmail.com>
sstone <sstone@users.noreply.github.com>
In the test data for DeterministicKeyChainTest all occurences of the (often invisible) 0x7f
character is replaced by its numerical literal "\177". This change is needed because a bug of
previous versions was fixed, which caused this character not being printed as text.
