Always create only two SimGear libraries: SimGearCore and SimGearStatic, regardless of whether we're building static or shared. This requires an updated to FindSimGear.cmake module, for the static configuration.
Determine name of library installation directory, i.e. "lib" vs "lib64",
which differs between all Debian-based vs all other Linux distros.
See cmake bug #11964, http://cmake.org/gitweb?p=cmake.git;a=commit;h=126c993d
Also provide a script for older (<=2.8.4) cmake
