This commit add testcases to test the following functions in bitcoin-tx:
- add a pay to non-standard script output
- add a P2SH output
- add a P2WSH output
- add a P2WSH wrapped in a P2SH output
- add a pay to pub key output
- add a P2WPKH output
- add a P2WPKH wrapped in a P2SH output
- add a bare multisig output
- add a multisig in P2SH output
- add a multisig in a P2WSH output
- add a multisig in a P2WSH wrapped in as P2SH output
Windows needed a few fixups to get the tests running:
1. bitcoin-tx needs a file extension in Windows. Take this opportunity to
add an env file, which pulls variables out of our build config. This can
be extended as needed, for now it's very simple.
2. After #1, split the args out of the exec key in the test data.
3. Correct the line-endings from windows stdout
