Package alt-packages: Information

- Added provides validation (thx Andrey Alekseev).

- Added
  + 'reload sources' action
- Fixed
  + dynamic translations
  + signature check is now only performed if pending state is active
  + source state indicator was not properly updated
- Changed
  + protocol selection is now preserved between different mirrors where possible
  + apply confirmation is now immediately shown on "disable" button click
  + updated to latest alterator-entry changes
  + reworked sources module user interface

- Changed (thx Andrey Alekseev):
  + new implementation of the repository management module (old "Repo" tab)
- Fixed (thx Andrey Alekseev):
  + progress dialog was resetting its scroll position with every message
  + progress dialog may not always be closable
  + possibility of closing progress dialog by alt+f4 while operation
    was still in progress
  + error dialog was not a top-level dialog
  + application was always suggesting updating database before upgrade,
    even if it was already updated