Rework the bookmark app to manage postgresql.
Add a fetchOne function into the PdoStmtWrapper
Fix a tipo in comments.

 * a notice would be reported if either of the 'cal' or 'event' $_GET params
   where not supplied, which would result in 'Cannot modify header information'
   warnings

 * the description field was removed in commit:
     f3f5d775
   but the field was still trying to be mapped - causing errors with CalDAV

checkWebserverUser would return the owner of the document
root instead of the owner of the web server process.

Signed-off-by: Florian Pritz <bluewind@xinu.at>