Cleanup of mostly asset files

- Fixes for all files
 - constexpr cleanup
 - Cosmetic changes
 - Remove punctuation from the end of messages

src/engine/moduleengine.cpp

@@ -42,7 +42,7 @@ namespace {
         "AllModules",
         "All Modules",
         "The list of all modules that were compiled for this version of OpenSpace in the "
-        "same order in which they were initialized."
+        "same order in which they were initialized"
     };
 } // namespace