Use duplicated imports list so that the default imports list does not get changed with every compiled script.
Only fire block and thread trace events in 2.0 mode.
Enable Ripper tests in 1.9 suite.
Implement Method#parameters for native methods.

In MRI, native methods will only present a list of :req for fixed-
arity methods or a single :rest for variable-arity methods. I have
duplicated this in JRuby, though I'd prefer to present the more
correct layout of required and optional args. I have filed a bug
with MRI to improve #parameters in this way:

https://bugs.ruby-lang.org/issues/8088

Fixes #583.
Properly check for Windows in resolv.rb. Fixes #580.
Merge pull request #579 from JonAdams1000/master

Don't include imports from previously processed ruby files in every generated java file.
Symbols can have encodings that need to be Marshaled

Add a new interface to the few special objects that can be Marshaled
with encodings.