Switch the license to be LGPLv2/later, with small parts still remaining as GPLv2/later, by agreement of major contributors

Defaults modified from original: alpha=200, key=F10

The huge item definition and item namespace unification patch (itemdef), see http://c55.me/minetest/wiki/doku.php?id=changes:itemdef

Collected and moved existing camera infrastructure from game.cpp to camera.cpp and camera.h. Introduced configuration settings 'fov' which chooses the camera's (vertical) field of view and 'view_bobbing' which currently does nothing. Other code refactored to not expect the FOV to be a build time constant.

Removed unused camera_position and camera_direction fields from Client. Moved ClientEnvironment::drawPostFx to ClientMap::renderPostFx -- this will make the camera management classes easier to write, as ClientMap already knows the camera position but ClientEnvironment doesn't and has to be told about it. This also eliminates the need for Client::getEnv(). Made the post effect color a content feature defined in content_mapnode.h.

And some simple animation when trying to dig...