Cleanup for coding style

Add strict mode to check_style_guide script

modules/volume/volumeutils.cpp

@@ -24,8 +24,7 @@
 
 #include "volumeutils.h"
 
-namespace openspace {
-namespace volume {
+namespace openspace::volume {
 
 size_t coordsToIndex(const glm::uvec3& coords, const glm::uvec3& dims) {
     size_t w = dims.x;
@@ -35,20 +34,19 @@ size_t coordsToIndex(const glm::uvec3& coords, const glm::uvec3& dims) {
 //    size_t x = coords.x;
 //    size_t y = coords.y;
 //    size_t z = coords.z;
-    
+
     return coords.z * (h * w) + coords.y * w + coords.x;
 }
 
 glm::uvec3 indexToCoords(size_t index, const glm::uvec3& dims) {
     size_t w = dims.x;
     size_t h = dims.y;
-    
+
     size_t x = index % w;
     size_t y = (index / w) % h;
     size_t z = index / w / h;
-    
+
     return glm::uvec3(x, y, z);
 }
 
-} // namespace volume
-} // namespace openspace
+} // namespace openspace::volume