Log Message:
Update ruby-parser to 3.8.1.

=== 3.8.1 / 2016-02-19

* 1 bug fix:

  * Fixed problems with tLONELY in mlhs_node.

=== 3.8.0 / 2016-02-18

* 1 major enhancement:

  * Added support for Ruby 2.3.0 and the &. operator. (presidentbeef)

* 2 minor enhancements:

  * Add support for safe attr assign. (presidentbeef)
  * Added support for safe call. (presidentbeef)

* 1 bug fix:

  * Fixed parsing of { 'a': :b }. (presidentbeef)