Fixed copy-paste error in FontMetrics.

Author: Dmitriy Kubyshkin

lib/FontMetrics.js

@@ -20,7 +20,7 @@ var FontMetrics = function(family, size) {
 
   // Now we can measure width and height of the letter
   line.innerHTML = 'm'; // It doesn't matter what text goes here
-  this._width = line.offsetHeight;
+  this._width = line.offsetWidth;
   this._height = line.offsetHeight;
 
   // Now creating 1px sized item that will be aligned to baseline
@@ -35,7 +35,7 @@ var FontMetrics = function(family, size) {
   // Baseline is important for positioning text on canvas
   this._baseline = span.offsetTop + span.offsetHeight;
 
-  document.body.removeChild(line);
+  // document.body.removeChild(line);
 };
 
 module.exports = FontMetrics;