M4: Attempt to fix the broken Rails code

I am not sure how this code could have ever worked without lots of
crashing, but maybe I am missing something... Still, casting an
arbitrary integer value to an int *pointer* and then later dereferencing
it does not seem like a good idea :).

Changed the code to do what I *guess* it was meant to do. But somebody
who actually knows M4 and its games should double check.

engines/m4/rails.cpp

@@ -61,9 +61,7 @@ void Rails::clearRails() {
 		delete tempNode;
 	}
 
-	for (i = 0; i < _edges.size(); i++) {
-		_edges.remove_at(i);
-	}
+	_edges.clear();
 
 	for (j = _noWalkRects.begin(); j != _noWalkRects.end(); ++j)
 		delete (*j);
@@ -246,7 +244,7 @@ void Rails::createEdge(int32 node1, int32 node2) {
 		} else {
 			distance = SqrtF16(FixedMul(deltaX, deltaX) + FixedMul(deltaY, deltaY)) << 8;
 		}
-		_edges.insert_at(index, (int16*)(distance >> 16));
+		_edges.insert_at(index, distance >> 16);
 	}
 
 	debugCN(kDebugCore, "node1 = %d, node2 = %d, valid = %d\n", node1, node2, valid);
@@ -312,7 +310,7 @@ int16 Rails::getEdgeLength(int32 node1, int32 node2) {
 	// Find the table entry i.e. tableWidth * node1 + node2 and then subtract
 	// n(n+1)/2, since only the upper triangle of the table is stored
 	index = (MAXRAILNODES-1)*node1 + node2 - 1 - (node1*(node1+1)>>1);
-	return *_edges[index];
+	return _edges[index];
 }
 
 void Rails::disposePath(RailNode *pathStart) {

engines/m4/rails.h

@@ -73,7 +73,7 @@ class Rails {
 
 private:
 	Common::Array<RailNode *> _nodes;
-	Common::Array<int16 *> _edges;
+	Common::Array<int16> _edges;
 	Common::List<NoWalkRect *> _noWalkRects;
 	M4Surface *_walkCodes;