Revert "Enable tests for Windows 8.1 (#251)"

This reverts commit 63e5fcc58b75a5a857e6cbfca09a0049c6d31010.
Use comma as separator for artifacts (#304)
Upgrade to Mozmill 1.5.23 (#310)
Disable daily tests on Win8.1 for esr builds too (#307)
Upgrade to Mozmill 2.0
Add 4th node for each platform and OS X 10.9 (#315)
Fix upgrade patch to Mozmill 2.0
Re-add email notification address (#317)
Enable OS X 10.9 machines for testing (#321)
Changed email notification sender to mozilla.org (#256)
Revert to Mozmill 1.5.24
Revert "Changed email notification sender to mozilla.org (#256) because it breaks the jenkins patches"

This reverts commit 32e2db6ae96009ab4bc058a1e8fa25b342b51fca.
Re-enable Windows 8.1 machines (#327)
Improve documentation for new contributors (#323)
Upgrade to Jenkins 1.509.4 (#298)
Update configuration files for plugin updates and how Jenkins saves them (#298)
Upgrade email-ext plugin to version 2.35.1
Don't send success triggered emails to our mozmill-ci list (#336)
Enable additional nodes for Endurance tests (#341)
Changed email notification to mozilla.org (#256)