Merge pull request #1148 from dannyvankooten/master

Take PHP timeouts into account to ensure a maximum of once a week, calls are now non-blocking. Props @dannyvankooten
Added curl and php version info in tracking
Merge branch 'master' of github.com:Yoast/wordpress-seo
Added extra attributes for tracking
Fix in curl version tracking
Actually use the WP_VERSION environment var when running Travis tests.
Remove \tabs from Travis file.
Travis uses Shell over Bash so fix string comparision.
Fix multi-line if-statement...
Disable WordPress 3.5.1 testing for now
Auto-deactivate plugin if SPL extension not available (prevent white-screen).
Fix issue 1160 - php notice / score title in publish box unavailable if post = noindex

Was a minor regression caused by pull request #1035.
Specify post ID when using wp_enqueue_media() to set up correctly for the post being edited.
Code style - spacing around if
The Premium product class is renamed in the next version of Premium so this check needs to change as well.
Clean up of i18n for extensions page as well as code clean up.
Merge branch 'master' of https://github.com/Yoast/wordpress-seo
Check whether snippet preview is shown on page before hiding / showing errors. Fixes #1178
Merge pull request #1155 from Petervw/master

Added extra attributes in tracking, so we can track PHP and CURL versions.
Fix wrong last modified date in sitemap, fixes #1136, #1161