It breaks backward compatibility than I thought. So it's disabled by
default. It means that REXML's XPath processor isn't compatible with
XPath 1.0. But it will be acceptable for users.

We can enable it by specifying "strict: true" to
REXML::XPathParser.new explicitly.

* lib/rexml/xpath.rb,
  lib/rexml/xpath_parser.rb: Accept "strict: true" option.

* test/rexml/test_contrib.rb,
  test/rexml/xpath/test_base.rb: Use not XPath 1.0 compatible behavior.

* test/rexml/test_jaxen.rb: Use XPath 1.0 compatible behavior.

* test/rss/test_1.0.rb,
  test/rss/test_dublincore.rb,
  spec/ruby/library/rexml/element/namespace_spec.rb,
  spec/ruby/library/rexml/element/namespaces_spec.rb,
  spec/ruby/library/rexml/element/prefixes_spec.rb: Enable again.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@63278 b2dd03c8-39d4-4d8f-98ff-823fe69b080e