Unable to send non-UTF8 strings

[jmthomas]

Sending a string containing data with invalid UTF8 strings (binary data) throws an exception. For example:

cmd("TGT", "PKT", { "DATA" => "\x90" }

Results in GeneratorError : source sequence is illegal/malformed utf-8

[jmthomas]

closed by https://github.com/OpenC3/openc3/pull/4