Changed tabkey handling for Iphtml. Sppeds up loading large pages of links considerably. maybe 100x
Fixed bug 21326 - PgUp PgDown etc didn't do anything.
Now up, down left, right, space, return, pgup and pgdown are handled.


git-svn-id: http://svn.freepascal.org/svn/lazarus/trunk@40505 4005530d-fff6-0310-9dd1-cebe43e6787f