fix some info about releasing, testing, etc
[skip ci]
address the fact that the new jruby-openssl gem does not require krypt any more

moved around the osgi integration tests to be easier managed
* fix version in GH-1983 test
* fix not more loadService debug
* fix list of activated gems
delete installed jars on clean to avoid packing old jars as well
fix enums to return nil on unknown symbol
sync/update ffi specs
fix failing variadic spec

updates variadic invoker to match MRI
variadic functions may now take enum arguments