Aggregator feature requests

Aggregator blocks, to optionally:

1. Change the block "weight" when a feed updates, so that the block with the most recently updated content "bubbles" to the top of a column.
2. Show the date/time of the most recent block contents. Eg. Last updated 3pm 20/12/2007, optionally at the top/bottom of the block.
3. Show the date/time of each titled item in a block.
4. Show the Description associated with each titled item in the block.

And the "Feed aggregator" content to be optionally assigned to a block.