BlenderDNA.h:

* Fix rethrow that would crash the program.
* QUESTION: am I throwing the right exception here.

COBLoader:
* catch exception by const ref
* fix equality checks using strncmp taht weren't actually checking equality

FBXMaterial: Catch exception by const ref (+ Debug log that it's done so)

FBXConverter: Rename local variables to avoid shadowing parameter

ImageExtractor: Remove duplicated/unreachable code

FBXConverter: Another shadowed variable fix

MD5Loader: 2 shadowed variables

IRRLoader: shadowed parameter

StepFileReader.cpp: Shadowed parameter

IRRLoader: remove empty else statement

STLExporter: Throw error instead of silently ignoring unimplemented option

Misc empty blocks removed or debug logging added

code/glTFExporter.cpp

@@ -245,7 +245,7 @@ inline Ref<Accessor> ExportData(Asset& a, std::string& meshName, Ref<Buffer>& bu
 
 namespace {
     void GetMatScalar(const aiMaterial* mat, float& val, const char* propName, int type, int idx) {
-        if (mat->Get(propName, type, idx, val) == AI_SUCCESS) {}
+        ai_assert(mat->Get(propName, type, idx, val) == AI_SUCCESS);
     }
 }