Update Jython and simplify its class path handling

This requires a corresponding merge https://github.com/ControlSystemStudio/maven-osgi-bundles/pull/6

Jython is updated to the 'latest' at this time.

In addition, custom code to hack the class loader so that jython scripts can access the opibuilder or scan classes have been removed, instead using 
```
Eclipse-RegisterBuddy: org.python.jython
```
in those plugins that should be accessible to jython code.

Fixes #110