Fixed bug in Feed_initSummary(i)

missing local variable declarations
Revised Feed_purgeDeleted(i)
Renamed Feed#N to FeedN#

and revised Feed_parseEntry(i, data)
Revised Feed_parseEntries(i, data)

with List_addItem
Generalized List_getItemField to List_getItem

Replaced i. a. FeedN?#%i%_timestamp