CKAN 2.5.2

Bug fixes: * Avoid submitting resources to the DataPusher multiple times (#2856) * Use resource.url as raw_resource_url (#2873) * Fix DomainObject.count() to return count (#2919) * Prevent unicode/ascii conversion errors in DataStore * Fix datastore_delete erasing the db when filters is blank (#2885) * Avoid package_search exception when using use_default_schema (#2848) * Encode EXPLAIN SQL before sending to datastore * Use ckan.site_url to generate urls of resources (#2592) * Fixed the url for the organization_item template