added new sanity-check assertions

fixed issue with angles [bad interface]
- adjusted other parts accordingly
- added corresponding test-cases
started working on absolute heading

grid/factory/v2/Importance.h

@@ -153,6 +153,8 @@ public:
 
 
 			// sanity check
+			Assert::isNotNaN(n1.walkImportance, "detected NaN walk importance for " + n1.asString());
+			Assert::isNotNaN(n1.navImportance, "detected NaN walk importance for " + n1.asString());
 			Assert::isTrue(n1.walkImportance >= 0, "detected negative walk importance. does not make sense!");
 			Assert::isTrue(n1.navImportance >= 0, "detected negative nav importance. does not make sense!");