* Initial commit of satellites test branch
* Modified code to work with batch TLE files from online links specified in .mod file. Does not yet auto-download the files.
* Added debug function to mod file for testing static points in orbit
* Fixed time offset bug that was corrupting satellite positions
* Minor changes for debug output and camera position.
* Changed to circle billboard for rendering satellite position
* Added satellite group name to each renderable title, and keyboard shortcuts for toggling visibility
* Added support for using ghoul luasocket lib to download latest satellite TLE files from celestrak.com
* Adding reference to updated Ghoul submodule containing luasocket changes
* Updating reference to latest Ghoul submodule in feature/satellites
* Updated reference to new ghoul version
* Updated reference to new ghoul submodule version for satellites
* Updated reference to new ghoul submodule version for satellits
* Updated versions of TLE files
* Added new Lua-accessible downloader available for scene loading
* Improved error handling for TLE files
* Updated submodule reference for ext/ghoul prior to luasocket addition
* Update SGCT reference
