Add remove-lines.js example

This example use GetStructuringElement, Dilate and Erode to remove line
of a music partition.

examples/remove-lines.js

@@ -0,0 +1,27 @@
+var cv = require('../lib/opencv');
+
+// Load the image
+cv.readImage('./files/note.png', function(err, im) {
+  console.log('plop');
+  if (err) { throw err; }
+  if (im.width() < 1 || im.height() < 1) { throw new Error('Image has no size'); }
+
+  im.cvtColor('CV_BGR2GRAY');
+  var bw = im.adaptiveThreshold(255, 0, 0, 15, 2);
+  bw.bitwiseNot(bw);
+
+  var vertical = bw.clone();
+
+  var verticalsize = vertical.size()[0] / 30;
+  var verticalStructure = cv.imgproc.getStructuringElement(1, [1, verticalsize]);
+
+  // Apply morphology operations
+  vertical.erode(1, verticalStructure);
+  vertical.dilate(1, verticalStructure);
+
+  vertical.bitwiseNot(vertical);
+  vertical.gaussianBlur([3, 3]);
+
+  // Save output image
+  vertical.save('./tmp/note.png');
+});