paypro: reorganize createPaymentTxSync.
paypro: extract addresses from server outputs and craft txs in this manner.
paypro: drop old tx code.
paypro: potentially use verbatim scripts after setting outputs.
paypro: stop using global $http.
paypro: use server outputs for creating txs again.
paypro: support user amount decision on 0-value-server-outputs.
paypro: prepare for txp refactor. will stay reverted until #1001 is merged.
Revert "paypro: prepare for txp refactor. will stay reverted until #1001 is merged."

This reverts commit c826acb3e539c4deb047053fd08a2a5e8fb8f8e8.
paypro: run paypro tests in browser. whitespace.
paypro: figure out why paypro tests are hanging in the browser.
paypro: tests - fix browser hanging.
paypro: debugging endianness issue in bignum (browser vs node).
paypro: try to keep everything big endian to avoid bignum bug in node.
paypro: fix mock server to handle txs as buffers when browserified. tests passing in browser.
Revert "paypro: deal with no unspent outputs. see #1043."

This reverts commit 6b5a618f0f7155c11ee734ef54ab3876b5923768.
paypro: tentatively reimplement commit that caused regression.
paypro: another tentative commit to avoid regression.
paypro: fix balance check regression in directive.
Revert "Revert "paypro: prepare for txp refactor. will stay reverted until #1001 is merged.""

This reverts commit 6fcd27b3ea0f7aa1ef7985560ca917393510c65e.