Adds spec for opening pipes in write mode via Kernel#open
Fix spec covering the encoding of Array#inspect with 1.9

Array#inspect uses the encoding of the string returned by Object#inspect
ran against the first entry of the array. Object#inspect will call
String#inspect, which does _not_ take into consideration the encoding of
the String object but will rather rely on the default external encoding.

Hence the spec must be rewritten to take into consideration the default
external encoding.
Improve specs for File.join using the rules given on [ruby-core:46804]

* Clarify the Windows part and specify the behavior of "\" on non-Windows
added a spec for DateTime.parse, initially added this to Rubinius but looks like it should go here
use describe as per recommendation of @dbussink
Merge branch 'master' of github.com:rubyspec/rubyspec
Merge pull request #150 from markburns/master

specs for DateTime.parse
Fix description and test the returned string is not equal?
remove duplicated example
Merge pull request #148 from eregon/file_join

Improve specs for File.join using the rules given on [ruby-core:46804]
non-ASCII Symbols need to be quoted to be parsed with 1.8
use Thread.pass in looping threads to ensure others get a chance to run
Update descriptions for Date.parse and DateTime.parse
Update specs for Refinements conforming to the latest spec described at <https://bugs.ruby-lang.org/projects/ruby-trunk/wiki/RefinementsSpec>.
Complex#marshal_dump and Rational#marshal_dump are private in Ruby 2.0.
Kernel#remove_instance_variable is public in Ruby 2.0.
Use send because Time#_dump is private in Ruby 2.0.
DateTime.parse("2012-11-08T15:43:61") raises an ArgumentError in Ruby 2.0.
Use send because Time#_load is private in Ruby 2.0.
String#lines, chars, and codepoints return arrays when no block given in Ruby 2.0.