Minor warning fix, and improvement to transaction signing API#94

Open

BadPirate wants to merge 2 commits intooleganza:masterfrom

BadPirate:master

Commits on Jan 24, 2018

Allow for signing inputs on existing transactions from outside of Builder (so you can load a transaction from a 3rd party, and sign it).
BadPirate
committed
Fix warnings about void being needed in non-prototype.
BadPirate
committed