Replace "wallet" with "address", in relation to hashcash's unilateral channel proposal. (#47)

* Update ch01.asciidoc

Propose to replace the comment regarding multi-sig wallet, with multi-sig transaction.

* Update ch01.asciidoc

ch01.asciidoc

@@ -40,7 +40,7 @@ Effectively the most recent update of the payment channel (encoded as a bitcoin
 In July of 2011, on the bitcointalk.org forum,  a pseudonomous user by the name of _hashcoin_ proposed the usage of Timelocks via the `nLockTime` function of the bitcoin network to solve the custody problem of exchanges.footnote:[Hashcoin on Bitcoin talk on July 4th 2011 - Instant TX for established business relationships (need replacements/nLockTime) http://web.archive.org/web/20190419103503/https://bitcointalk.org/index.php?topic=25786.0]
 The idea was to be able to quickly trade / sell Bitcoin without the necessity to send all the bitcoins to the exchange in the first place.
 Hashcoin effectively proposed what we would call an unidirectional payment channel today.
-With this mechanism a user A could fund a multisig wallet between A and another user B together with a timelocked transaction sending all Bitcoin Back to A.
+With this mechanism a user A could fund a multisig address between A and another user B together with a timelocked transaction sending all Bitcoin Back to A.
 The funding tx would not be signed and broadcasted by A before B provided a signature for the spend.
 Hashcoin imagined user B to be an exchange.
 Whenever user A wanted to send Bitcoin to user B user A could create a newer spend of the funding transaction which would send less Bitcoin back to A and more bitcoin to B.