fix: Convert Heartbeat to Scala

Signed-off-by: Jussi Virtanen <jussi.virtanen@valotrading.com>
fix: Convert Logout to Scala

Signed-off-by: Jussi Virtanen <jussi.virtanen@valotrading.com>
fix: Convert ResendRequest to Scala

Signed-off-by: Jussi Virtanen <jussi.virtanen@valotrading.com>
fix: Convert SequenceReset to Scala

Signed-off-by: Jussi Virtanen <jussi.virtanen@valotrading.com>
fix: Convert TestRequest to Scala

Signed-off-by: Jussi Virtanen <jussi.virtanen@valotrading.com>
Merge pull request #154 from jvirtanen/cleanups/fix-message

Clean up FIX messages