#256461: Allow individual panel pane styles. This requires a small modification to existing panel styles so that panel styles don't conflict with pane styles, but it is very minor, and very few panel styles are out there yet.

Move panels_render_pane to panels_pane_render_content and create panels_render_pane() to encapsulate theme_panels_pane for use on individual pane styles.

#260221 by sun, Pancho. Primarily codestyle cleanup; also fixed some missing leading slashes that were causing the edit icons not to appear in the new helptext for the display editor.

#205611: (By Wim Leers): Code style cleanup for panels styles, plus API standardization (note: This means some minor API changes).

Administrative looks and a hook_panels_pane_content_alter so modules can muck with pretty much anything on pane output.

Fix wrong title when argument not specified; fix 404 when argument asks for 404; fix too much CSS on rounded_corner style; fix missing div on rounded corner style when no id on panel

A rounded corners style; moved the style settings to pair with the layout settings; now all panel types can have styles.