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).
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