Bumped version to 0.4.3

Bumped version to 0.4.3 and set Label text format to rich text.
Trimming map names

All map names are trimmed from leading and tailing whitespaces so that
they can be in alphabetical order.
Fixed MyMapsPage

Model now resets when loading MyMapsPage so that it shows any newly
downloaded files.
Fixed MyMapsPage and BusMapsPage

Deleting last items from a long list(~25) no longer deletes a different
item than was requested by user. Also Changed header title on MapsPage.
Delete all maps feature

It is now possible to delete all maps that have been previously
downloaded by user from MyMapsPage.
Fixed ChangelogPage

Just a grammar fix.