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normal Go tests to help ensure it doesn't get out of date with the code.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 change updates the doc.go documentation file with the correct use
of the new (since 8eead5217d) API used
for passing additional options when creating new script engines.
Spotted by davec@
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.
