update installer mysqli_connect to only use port if defined
trim received feed data on fetch
subscribe: verify XML before adding to the database; fetch: try to work around entity problems if initial parsing fails
update_rss_feed: simplify debug reporting
remove debug_enabled global
better handle get_link() enabled plugins crashing on load
implement plugin API version compatibility check
plugins: bump API version
fetch: support if-modified-since without CURL
correctly report fetch error
Merge remote-tracking branch 'upstream/master'