Lots of backports from trunk to get rid of known issues in 0.4:

- Various fixes related to finding and fixing possible memory leaks.
- Added a Wikipedia icon and a pointer towards the entry.
- Give visual feedback if the mouse hovers placemarks.
- Give visual feedback if the mouse drags the planet.
- Position and Altitude display in StatusBar for KDE frontend.
- Added Statusbar items to the Qt-Marble frontend.
- Introducing different Notations: Decimal and Sexagesimal (DMS).
- Put tile creation into a worker thread and adopted the TileCreationDialog
- Improved HttpFetchFile by encoding the path url correctly, adding User-Agent and support
for HTTP redirect, now all city names are loaded correctly from WikiPedia
- Read the HTML pages as UTF-8, now the webpages look a lot better
- Guess the wikipedia domain to use by examine the $LANG variable, so 'LANG=sv marble' will use the swedish wikipedia site ;)
- Refactored HttpDownloadManager and HttpFetchFile by introducing StoragePolicy.
- Fixed the TinyHttpBrowser to show images and load style sheets.
- Add DiscCache class