Prevent directory access
Merge branch 'master' of git://github.com/Yoast/wordpress-seo into Prevent-directory-access
Merge pull request #1220 from jrfnl/Prevent-directory-access

Prevent directory access
Update license submodule
Remove leading slash as WP_DEVELOP_DIR already contains a trailing slash.
Fixed caching for paginated sitemaps.
Added missing post title field to the attachments query.
Prevented unsetting shared attachments array inside the loop.
Disabled sitemap debug output if error display configured to off.
Adjusted processing of image attachments for new structure of queried data array.
Fixed usage of attachment URL return (string, not array).
Refactor replace vars: move away from singleton pattern

-> Changed a few properties and methods to static to make them available to all instances while only having to set them up once (efficiency). Applies to the registration of new replacement variables and the help text methods
-> Changed class calls to be in line with this change

Also: fixed issue where post title replacement was still playing up, this will probably fix the issues people using the Optima Express plugin were still having
Refactor replace vars: removed superfluous array cast as this is done on the receiving end anyways
Merge branch 'Replace-vars-no-more-singleton' into Tests-for-replace-vars
Fixed/improved some var replacement tests
Refactored image_url() to only resolve upload directory once for performance.
Updated to use internal image_url() method over API.
Normalized home URL resolution everywhere to use stored value from property.
Stored charset information in property to eliminate get_bloginfo() calls inside loops.
Merge pull request #1233 from Rarst/sitemap-fixes

Sitemap fixes