There are several parts to this ticket:
1) Produce javaaddons-1.0.jar, a standalone JAR defining a (versioned)
Java interface suitable for consumption by third-party Java addon
implementations.
2) Support the new V1 interface in the JavaAddonManager.
3) Add Robocop JavascriptTests testing the JavaScript message passing
interface to and from Java.
This patch can be read as "not in tests/" and "everything in tests/".
