Use other approximation of rectangular node radius

Use the half height instead of the half diagonal length as radius,
because it's the worst case and doesn't produce too long links.

Author: linkvt

src/webvowl/js/elements/nodes/RectangularNode.js

@@ -9,7 +9,8 @@ module.exports = (function () {
 
 		var that = this,
 			height = 20,
-			width = 60;
+			width = 60,
+			smallestRadius = height / 2;
 
 
 		// Properties
@@ -29,7 +30,7 @@ module.exports = (function () {
 		// Functions
 		// for compatibility reasons // TODO resolve
 		this.actualRadius = function () {
-			return width;
+			return smallestRadius;
 		};
 
 		this.distanceToBorder = function (dx, dy) {

src/webvowl/js/elements/properties/BaseProperty.js

@@ -5,7 +5,8 @@ module.exports = (function () {
 
 	// Static variables
 	var labelHeight = 28,
-		labelWidth = 80;
+		labelWidth = 80,
+		smallestRadius = labelHeight / 2;
 
 
 	// Constructor, private variables and privileged methods
@@ -379,7 +380,7 @@ module.exports = (function () {
 	};
 
 	base.prototype.actualRadius = function() {
-		return base.prototype.width() / 2;
+		return smallestRadius;
 	};
 
 	base.prototype.textWidth = base.prototype.width;