* Added sanitation/improved validation to $_GET and $_POST variables if/when they are used in a manner which could cause security issues

* Moved loading of our text domain forward from wp_loaded to the init action as advised in the codex and registered the translating of default options to be run straight after

* Renamed a number of options within the wpseo_titles option as they ran the risk of being overwritten by post type/taxonomy options which could get the same name
* Added property $variable_option_name_patterns to deal with which these kind of keys which *may* need to be allowed to stay in the options domains, even if the post type/taxonomy it is for, at the time of validation, does not exist yet. Added retain_variable_keys() method for that same purpose.
* Resorted to called enrich_defaults() a lot more often than I would like, to allow for new post types and taxonomies being added during the run

* Solved the problem of adding back our default filters in the update_option() function - even when the update would fail (previously they were only added back if the update succeeded, causing a security hole)