Feature/satellites (#2185)

* Remove planet geometry and simplespheregeometry
* Only use a single TLE loading implementation
* Add caching to the satellite loader;  Add Lua function to load kepler file
* Fix RenderablePlanetProjection specification
* Add OMM loading funtion;  Remove mean motion from Kepler parameters
* Replace TLETranslation class with GPTranslation and support OMM files
* Support loading SMDB files in kepler functions
* Merge RenderableSatellites and RenderableSmallBody with RenderableOrbitalKepler
* Update submodules
* Adapt existing satellites to new OMM file type
* Remove TLE helper
* Remove SSSB shared file and adapt sssb assets

apps/OpenSpace/ext/launcher/src/filesystemaccess.cpp

@@ -87,7 +87,7 @@ void FileSystemAccess::parseChildFile(std::string filename, bool& hasDirHeaderBe
     else {
         std::string extension = filename.substr(filename.length()
             - _fileExtension.length());
-        if (extension.compare(_fileExtension) != 0) {
+        if (extension != _fileExtension) {
             return;
         }
     }

apps/OpenSpace/ext/launcher/src/profile/propertiesdialog.cpp

@@ -352,7 +352,7 @@ void PropertiesDialog::editBoxDisabled(bool disabled) {
 
 void PropertiesDialog::parseSelections() {
     // Handle case with only one remaining but empty line
-    if ((_propertyData.size() == 1) && (_propertyData.at(0).name.compare("") == 0)) {
+    if ((_propertyData.size() == 1) && _propertyData.at(0).name.empty()) {
         _propertyData.clear();
     }
     *_properties = std::move(_propertyData);