Core/maps.py: Added PlanetHistory.load() method.

Signed-off-by: Martin Stone <martin@d7415.co.uk>
(cherry picked from commit 74e8aba28af5a6ad80cb62f97433c4a37676e069)
parser.py: Fixed the News Scan parser to attach entries to the correct planet.

Signed-off-by: Martin Stone <martin@d7415.co.uk>
(cherry picked from commit bc1b3e6884d08dfcfe3c211ec4cd96bbbb32eb10)
parser.py: Fixed the initial scan-planet link to use PlanetHistory.

Signed-off-by: Martin Stone <martin@d7415.co.uk>
(cherry picked from commit 3b5a5d654b02e80a5f734ea754c8c44b8d42801b)