Reverse and push further the idea of offscreen preparation as done in commit f30312b. We add and remove cells in a view hierarchy which from now has a height of three times the height of the visible rectangle; so we are able to quickly respond to `pageDown` and `pageUp` requests. Fix ViennaRSS/vienna-rss#229 ; should probably fix issue #20 too.
…nsed under the New BSD license)
…e List View. Updated README to document this.
…eger. Adjust your code or your row heights will be very screwy!