improve EIS developer documentation

[Wouter1]

The javadoc needs some improvement to give a better overview. Maybe we should add some more overview documentation.

For instance, I'm returning a Boolean from EIS2Java. Now where do I find to what EIS.iilang object this boolean is translating? How do I even figure out that this is in the translation package?

Also developers may want to use the bare EIS interface directly. Where is the requirements documentation? How do they know if it's necessary? Are there examples how to do that?

[Wouter1]

Added notes in the docu on

sharing the jvm

sharing awt

importance of robustness of management functions for small fails in the code,

[Wouter1]

I see we have a section on translation

https://github.com/eishub/eis/wiki/Creating-an-Entity