Added the maps-module to the iwmlib.

Migrated a  ot of the content from the tuesch to the iwmlib.
This is before the decoupeling of the layers.

lib/pixi/maps/projections/projection.js

@@ -0,0 +1,43 @@
+/**
+ * A projection determines how a geographical card has to
+ * be interpreted to map coordinate to pixels.
+ *
+ * Most used transformation is the mercator projection,
+ * which projects a sphere on a cylinder.
+ *
+ * @abstract
+ */
+
+export default class Projection {
+    /**
+     * Transforms a coordinate to a normalized position on the map.
+     *
+     * @param {*} coords
+     * @memberof Projection
+     */
+    forward(coords) {
+        console.error('You must override the forward function in ' + this.name + '.')
+    }
+
+    /**
+     * Transforms a normalized point on the map to a coordinate.
+     *
+     * @param {*} point
+     * @memberof Projection
+     */
+    backward(point) {
+        console.error('You must override the backward fuction in ' + this.name + '.')
+    }
+
+    toString() {
+        return 'Projection (abstract)'
+    }
+
+    get name() {
+        return this.toString()
+    }
+
+    get maxViewport() {
+        return { min: new PIXI.Point(-90, -180), max: new PIXI.Point(90, 180) }
+    }
+}