Preparations for statusnet connector import
Removed deprecated twitter code, since twitter had changed its API long time ago.
When converting to plain text, links behind @-addresses are now removed
Diaspora: The HTML paragraph element was treated wrong when importing items from Diaspora
The system's load is now checked, when the cronhooks are started.
The function to fetch data about a site (via the "parse url" function) is moved from diaspora to another place, since it is multi purpose
When converting from html to bbcode, now mail links are converted into the [mail] bbcode
New function "original_url" (moved from an addon) that follows all redirects to the original url.
oembed: Now it is possible to use the service from embedly with an API key.
parse url: Emtpy values in meta headers are now ignored. Oembed data has priority. Videos are embedded with some further information.
Code beautification and some more logging data - no changes in the functionality.
Vier: Added treatment of videos like links. (See the changes in the "parse url" section)
Merge pull request #932 from annando/master

Preparation for bidirectional statusnet sync, functions moved from addons into the core and some converting stuff