Added ScenePreProcessor helper class to add missing dummy animation channels.

Modified FindInvalidData's behaviour regarding animation channels
Futher work on the IRR scene and IRRMESH loaders. Q3D fix. 
Updated aiNodeAnim documentation.

git-svn-id: https://assimp.svn.sourceforge.net/svnroot/assimp/trunk@218 67173fc5-114c-0410-ac8e-9d2fd5bffc1f

code/Importer.cpp

@@ -51,6 +51,7 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #include "DefaultIOSystem.h"
 #include "GenericProperty.h"
 #include "ProcessHelper.h"
+#include "ScenePreprocessor.h"
 
 // Importers
 #ifndef AI_BUILD_NO_X_IMPORTER
@@ -565,6 +566,10 @@ const aiScene* Importer::ReadFile( const std::string& pFile, unsigned int pFlags
 		// if successful, apply all active post processing steps to the imported data
 		if( mScene)
 		{
+			// FIRST of all - preprocess the scene 
+			ScenePreprocessor pre;
+			pre.ProcessScene(mScene);
+
 			DefaultLogger::get()->info("Import successful, entering postprocessing-steps");
 #ifdef _DEBUG
 			if (bExtraVerbose)