Use an array of values instead of object literals to save space in fontMetricsData.js

Test Plan: make test

Reviewers: emily

src/fontMetrics.js

@@ -122,11 +122,19 @@ var metrics = {
 var metricMap = require("./fontMetricsData");
 
 /**
- * This function is a convience function for looking up information in the
+ * This function is a convenience function for looking up information in the
  * metricMap table. It takes a character as a string, and a style
  */
 var getCharacterMetrics = function(character, style) {
-    return metricMap[style][character.charCodeAt(0)];
+    var metrics = metricMap[style][character.charCodeAt(0)];
+    if (metrics) {
+        return {
+            depth: metrics[0],
+            height: metrics[1],
+            italic: metrics[2],
+            skew: metrics[3]
+        };
+    }
 };
 
 module.exports = {