Test updated for #1582 to make it smaller
SourceDeclarationVisitor #1576: do not visit native stuff
Naming #1576: Fixed a method that was a bug waiting to happen and added another to get the class name for a toplevel decl
MissingNativeVisitor #1576: Visit native decls and use-sites to add errors when missing
Test for #1576: Java compiler attempts to access native method
MiscTest: do not compile Throwable and printStackTrace natives in language module
cosmetic: Ceylonvisitor: reindent to get rid of tabs