Refactor interal codes
Improve codes
Avoid potential NUL char comparison bug
Improve code readability
Increase the flexibility of RubyArray API by accepting Collection in
certain methods

Change Comparable<RubyArray> to Comparable<List> in RubyArray
Fix the potential bug of new RubyString(CharSequence)
Add test
Improve interal codes
ByteUtil#fromBinaryString & ByteUtil#fromHexString now can accept empty
String
Improve the JavaDoc of RubyEnumerator & RubyLazyEnumerator
Improve the quality of entire JavaDoc
Trim JavaDoc
Deprecate RubyCollections#newRubyString
Enhence RubySrtring JavaDoc