fix and improvement on item time tracking
cleanup
use item GUID or ID provided by SimplePie as basis for item id

better support of Items whose link change at every refresh (eg Google
alerts)
Revert "use item GUID or ID provided by SimplePie as basis for item id"

This reverts commit 40b2708f9fe3f6c3eea20916f9d4bc534695d5fc.
correct item id handling

commit with correct files
support for title-less items, leave summary as is
template updates
some layout changes on admin pages
more logging
filter support for limiting feed size in all modes
create http object only if at least one feed to update
admin pages: better mobile support
minor admin pages fixes
code cleanup
fixes for view by feed
cleanup of default values
fix of cron updater
template fix for legacy features