Complete commit 57dbe3e01a8b4b03eaba705032cf6c6f42b06f12
Fix issue #1104 - regression issue with %%name%% variable

My fingers are itching to rewrite this whole function as it seems to be causing more and more issues. Will do when I have the time, which unfortunately probably won't be all that soon.
Merge branch 'master' of git://github.com/Yoast/wordpress-seo into Issue-1104-regression-in-var-replacements
Merge branch 'master' of git://github.com/Yoast/wordpress-seo into Meta-snippet-help
Added first basic wpseo_replace_vars test.
Replace the %%strings%% always
Optimized preg_replace in replace vars
Some plugins add posts with a post_date but without a post_date_gmt. Sitemap now uses post_date if the post_date_gmt is 0.
Merge pull request #1102 from jrfnl/Meta-snippet-help

Complete commit 57dbe3e01a8b4b03eaba705032cf6c6f42b06f12
Merge pull request #1108 from jrfnl/Issue-1104-regression-in-var-replacements

Fix issue #1104 - regression issue with %%name%% variable
Changelog update.
Added support for %%tag%% even if the ID is empty.
Related #1111
Small improvements to the REGEX that strips all remaining not replaced title vars
Merge branch 'pr/1121'
Changelog update.
Version bump to 1.5.3.1
Small read me update
Backing out earlier change, as this breaks the snippet preview.
Changelog update.
Version bump to 1.5.3.2