Compile a useful subset of FG as a shared library, and add two basic
uses of this to exercise some Flightplan / RoutePath / navaid
functions.
The test framework can/will be expanded incrementally from here, this
is just a starting point.
The precipitation branch of the OSG scene graph is now centrally managed by the
scenery manager rather the precipitation manager itself. The scene graph
initialisation from the constructor has also been shifted into the new
FGPrecipitationMgr::sceneGraphSetup() function.
This class and their source files visual_enviro.[h|c]xx were
unused since OSG transition. It's only functionality was to
keep a variable for the enable-state of rendering of precipitation.
This has now been moved to SGPrecipitation.
This patch also removes all references to this class and
visual_enviro.hxx. Wxradar needs a new implementation for cloud
echoes which probably should be part of fgclouds.
See also SimGear commit 4e6159aa07f2817c09fad72db64d713e47f6f3da
Reindent to Stroustrup style.
Make FGPrecipitationMgr an SGSubsystem and remove all references to it
in main.cxx and renderer.cxx.
Use SGGeod::makeZUpFrame instead of a private function in
tileentry.cxx. Rewrite that function, WorldCoordinate, to use
makeZUpFrame too.