Feature/gaia mission merge (#766)

* Add Adam Aslegård's module that renders Gaia mission stars
 * Add module for Gaia mission
 * Add CCfits and cfitsio submodules and the implemented fitsfilereader module from the OpenSpace-sun-earth-event branch
 * Add a TaskRunner to read from a fits file

modules/server/src/jsonconverters.cpp

@@ -33,12 +33,6 @@ using json = nlohmann::json;
 
 namespace openspace::properties {
 
-namespace {
-
-
-
-} // namespace 
-
 void to_json(json& j, const Property& p) {
     std::string description = p.generateBaseJsonDescription();
     json desc = json::parse(description);