Univalue: Do not build JSON escape list at runtime
No need to waste startup time building something that can be done
at compile time.
This also resolves a clang++ warning originally reported in #4714,
univalue/univalue_write.cpp:33:12: warning: array subscript is of type 'char
escapes['"'] = "\\"";
Add "bitcoin-tx" command line utility and supporting modules.
This is a simple utility that provides command line manipulation of
a hex-encoded TX. The utility takes a hex string on the command line
as input, performs zero or more mutations, and outputs a hex string
to standard output.
This utility is also an intentional exercise of the "bitcoin library"
concept. It is designed to require minimal libraries, and works
entirely without need for any RPC or P2P communication.
See "bitcoin-tx --help" for command and options summary.