This commit adds an example test file so it integrates nicely with Go's
example tooling.
This allows the example output to be tested as a part of running the
normal Go tests to help ensure it doesn't get out of date with the code.
It is also nice to have the example in one place rather than repeating it
in doc.go and README.md.
Links and information about the example have been included in README.md in
place of the example.
This commit modifies the code to no longer require a protocol version. It
does this by making use of the new Serialize function in btcwire.
Unfortuantely this does entail a public API change which I generally don't
like to do, but eliminating the usage of the protocol version throughout
the codebase was important enough to warrant the change.
btcscript contains an amount of debug logging that is very useful to
have. We have agreed that testing this isn't realy practical or indeed
really useful and thus is rather unlikely to grow test coverage any time
soon.
