removed heading::rnd (not seedable)

fixed grid-walker issues when conducting multiple runs
new helper methods for the interpolatorr

math/Interpolator.h

@@ -34,6 +34,12 @@ public:
 		entries.push_back(InterpolatorEntry(key, value));
 	}
 
+	/** get the smallest added key */
+	Key getMinKey() const {return entries.front().key;}
+
+	/** get the largest added key */
+	Key getMaxKey() const {return entries.back().key;}
+
 	/** get the interpolated value for the given key */
 	Value get(const Key key) const {