remove legacy (and or deprecated) code

[marscher]

• convertStrings option has been deprecated since version 0.8x or so.
• The old JPackage system is only for python2 series and generates lots of deceptive classes. At some point these two are going to have to go away.

[astrelsky]

I'm opposed to removing the convertStrings option. Having to manually convert python and java strings back and forth makes using Java apis requiring a string unnecessarily difficult to use and increases the learning curve for new users. While it may not be efficient to constantly convert back and forth in the backend, I personally think the ease of use out ways the runtime cost, especially if the alternative is having to manually convert them which has the same cost anyway.