Bugfix: fixed a bug that occured when vertex had more than 4 weights but the first 4 weights were not attached to any bone.

git-svn-id: https://jmonkeyengine.googlecode.com/svn/trunk@10233 75d07b2b-3a1a-0410-a2c5-0572b91ccdca

engine/src/blender/com/jme3/scene/plugins/blender/modifiers/ArmatureModifier.java

@@ -333,7 +333,7 @@ import com.jme3.util.BufferUtils;
 								} else if(weight > 0) {//if weight is zero the simply ignore it
 									warnAboutTooManyVertexWeights = true;
 									Entry<Float, Integer> lowestWeightAndIndex = weightToIndexMap.firstEntry();
-									if(lowestWeightAndIndex.getKey() < weight) {
+									if(lowestWeightAndIndex != null && lowestWeightAndIndex.getKey() < weight) {
 										weightsFloatData.put(lowestWeightAndIndex.getValue(), weight);
 										indicesData.put(lowestWeightAndIndex.getValue(), boneIndex.byteValue());
 										weightToIndexMap.remove(lowestWeightAndIndex.getKey());