Do not depend on console to properly encode to proper tty-friendly chars on windows if the JVM was started without a console.
Implement EmptyFileResource
Always return same instance
Keyword arguments error checking mildly improved
Argument error on required keyword arguments
Merge pull request #1513 from ratnikov/null-file-resource

Introduce EmptyfileResource that should replace the JRubyNotFoundFile.NOT_FOUND
Implement EmptyFileResource
Always return same instance
Merging with jruby-1_7
use snapshot version [skip ci]
Some more kwargs error work++
post_reqd_arg already knows about kwargs
Refactor optarg logic (no fixes)
Another round of kwargs refactoring
Receive arguments know enough to extra proper kwargs value itself (fixes issue that interpreter did not know 100% if last hash args was a kwarg or not
Remove dead method after last round of refactoring
fix tyop
remove dead code
[Truffle] - Using putIfAbsent to add a new RubySymbol in the SymbolsTable.

Thanks @thedarkone to help us with that. Without putIfAbsent multiple
threads might concurrently call createSymbol with the same String name,
create a bunch of RubySymbols, store them in symbolsTable (overwriting
each other) and then return them to rubyland. But using putIfAbsent we
avoid this behaviour.
[Truffle] - OpenModuleNode should handle only with Truffle Nodes.

We should not mix AST nodes with Truffle Nodes in the same class (Except
the Translator class).
Translator.java is the class responsible to convert AST Nodes into
Truffle Nodes. All the rest of the code related to Truffle should only
deal with Truffle Nodes.