- manually merged C4D importer code from acgessler branch

- manually merged IFC bugfixes and improvements from schrompf branch

code/ImporterRegistry.cpp

@@ -170,6 +170,10 @@ corresponding preprocessor flag to selectively disable formats.
 #   include "AssbinLoader.h"
 #endif 
 
+#ifndef ASSIMP_BUILD_NO_C4D_IMPORTER
+#   include "C4DImporter.h"
+#endif
+
 namespace Assimp {
 
 // ------------------------------------------------------------------------------------------------
@@ -297,6 +301,10 @@ void GetImporterInstanceList(std::vector< BaseImporter* >& out)
 #if ( !defined ASSIMP_BUILD_NO_ASSBIN_IMPORTER )
 	out.push_back( new AssbinImporter() );
 #endif
+
+#ifndef ASSIMP_BUILD_NO_C4D_IMPORTER
+	out.push_back( new C4DImporter() );
+#endif
 }
 
 }