impr(bpmnrenderer): multi line label support for lanes

Lane labels can be two lines long.
Later improvement: If label is longer as two lines align it at container bottom so that text leaves lanes to the left or scale text size or cut text with '…. '

lib/draw/BpmnRenderer.js

@@ -275,12 +275,21 @@ function BpmnRenderer(events, styles, bpmnRegistry, pathMap) {
   }
 
   function renderLaneLabel(p, text, data) {
-    // position text left top
-    var textBox = renderLabel(p, text, {height: data.width, width: data.height}, 'left-top');
-    // rotate text and center it on the middle of the lane height
+    var textBox = renderLabel(
+      p,
+      text,
+      {
+        height: 30,
+        width: data.height
+      },
+      'center-middle'
+    );
     var bbox = textBox.getBBox();
-    var top = (data.height / 2) + (bbox.width / 2);
-    textBox.transform('translate(0,' + top + ') rotate(270)');
+    var top = -1 * data.height;
+    textBox.transform(
+        'rotate(270) ' +
+        'translate(' + top + ',' + 0 + ')'
+    );
   }
 
   var handlers = {