Merge pull request #277 from sq5gvm/master

Updated polish (pl_PL) translation
add af plugins for nagional geographic and sciam
af_natgeo: remove some unneeded elements
fix af_sciam
remove unused old-style image rewritign
add plugin to cache images in starred articles; pass article_id to
sanitize
add hook_house_keeping
make cache starred plugin use hook_house_keeping
api: pass article id to sanitize
rss: force language to 2 characters; run house keeping hooks properly
fix entries not inserted properly when no languages are detected
rollback current transaction before trying to report SQL query errors, properly save database error messages when logging query errors
improve support for feeds with invalid unicode entities
API should return excerpt when asked
parser: support media:content elements within media:group
simplify media:content xpath
support media:description for media: enclosures
Merge pull request #279 from mhaley/patch-1

API should return excerpt when asked
do not use iconv in tag_is_valid, data should be utf8 anyway at this point; remove sanity check for iconv because parser does not use it