imagecache 5.x-2.2

Changes since DRUPAL-5--2-1:

• #266268 by moonshine, add sharpen filters to imagecache.
• #241541 by soxofaan, fix imagecache test to work around url()'s static cache issue.
• requirements rearranging... trying to clean up upgrade path since the display settings are broken.
• #260669 by hanoii: Imagecache field formatter is generating broken output when no actual image (or default) is available.
• #259220 by drewish: Backporting _imagecache_recursive_delete() from the D6 version.
• #311813 by thePanz: Warning on Flush of a Preset.
• #294538 by davidwhthomas: Postgres support for imagecache_update_4().