HH-31965 xml testing helpers, XmlResponseTestCase mixin and tests for them
HH-31965 Add to .gitignore rules for OS X & Windows junk
HH-31965 fix "text not equals" error's unicode issues
HH-31418 fix XmlResponseTestCaseMixin's inheritance, fix test name
HH-31965 fix xml text nodes compare
Merge branch 'HH-31965' into release-candidate
release 2.17.4