Updated documentation according to latest forge Wiki updates

src/site/markdown/index.md

src/site/markdown/tutorials/direct-location-with-DEM.md

src/site/markdown/tutorials/direct-location.md

src/site/markdown/tutorials/inverse-location.md

src/site/markdown/tutorials/tile-updater.md

src/site/resources/images/Earth_FlatVsRugged.gif

src/site/resources/images/RuggedExplained.png

src/site/site.xml