Added skip & take parameters.
This functionality gives us an ability to control load process and do not serve the old content.

Definitions:
take - on the iteration start skipCount feeds will be showed even if they belong to the list of read feeds.
skip - count of the feeds which should be hidden during one iteration.
Iteration map: take, skip, take, skip, take, skip,...
updated extension version
Merge pull request #1 from TKadik/v1.1

V1.1