Move newRubyArray(), newRubyHash(), newRubyEnumerable(),
newRubyRnumerator(), newRubyRange() to RubyCollections
Remove U(), X(), Ⴖ(), ㄍ(), ㄧ(), 十() from RubyArray
Add IterableMap and minor change the implementation of RubyHash
Made RubyEnumerable an abstract class
Avoid null parameters for constructors
Apply Guava Preconditions
Modify JavaDoc for blocks
Handle stream closing properly for RubyIO & RubyFile
Update README.md
Refactor foreach() of RubyIO
Ready to release version 1.3.0