Merge pull request #32 from NiklasMM/fix/filter_url_list

Fixed url filtering.
First early version of management app
App can now read feeds file and put the data into the table.
Added checkboxes to hide feed.

    Hidden feeds will remain in the feed list, but won't be displayed in the applet
Added function to read the entries from the table
Added functionality to remove entries.
Added add_feed button and fixed issue with delete.
Added listeners to url and title change.
Added checkbox functionality.
Feed file is now written upon save.