added new sanity checks and compile-time assertions to prevent errors

fixed stair-building issue
new test-cases
added elevator support
fixed/improved some walker modules

Assertions.h

@@ -67,7 +67,6 @@ namespace Assert {
 		if (std::abs(v1-v2) > delta) {doThrow(err);}
 	}
 
-
 	template <typename T, typename STR> static inline void isBetween(const T v, const T min, const T max, const STR err) {
 		if (v < min || v > max) {
 			std::stringstream ss; ss << "\n[" << min << ":" << max << "] but is " << v << "\n";
@@ -77,4 +76,24 @@ namespace Assert {
 
 }
 
+namespace StaticAssert {
+
+	// yes and no have a different size so sizeof(yes) != sizeof(no)
+	using yes = uint32_t;
+	using no = uint64_t;
+
+	template<class BaseClass, class SubClass> struct isXbaseOfY {
+		static yes test(const BaseClass&);									// will be chosen if X is base of Y
+		static no  test(...);												// will be chosen otherwise
+		static const SubClass& helper();
+		static const bool value = sizeof(test(helper())) == sizeof(yes);	// true if test(const B&) was chosen
+	};
+
+	template <typename A, typename B> static inline void AinheritsB() {
+		static_assert(isXbaseOfY<B, A>::value, "A does not inherit from B!");
+	}
+
+
+}
+
 #endif // ASSERTIONS_H