added docstrings to the customlogging.js sample

+/**
+ * A basic custom logging implementation. The idea is to (extremely) verbosely
+ * log every received resource.
+ *
+ */
 phantom.injectJs('casper.js');
 
 var casper = new phantom.Casper({
+    /**
+     * Every time a resource is received, a new log entry is added to the stack
+     * at the 'verbose' level.
+     *
+     * @param  Object  resource  A phantomjs resource object
+     */
     onResourceReceived: function(self, resource) {
         var infos = [
             resource.url,
@@ -14,12 +25,14 @@ var casper = new phantom.Casper({
         });
         self.log(infos.join(', '), 'verbose');
     },
-    verbose: true,
-    logLevel: 'verbose'
+    verbose: true,      // we want to see the log printed out to the console
+    logLevel: 'verbose' // of course we want to see logs to our new level :)
 });
 
+// add a new 'verbose' logging level at the lowest priority
 casper.logLevels = ['verbose'].concat(casper.logLevels);
 
+// test our new logger with google
 casper.start('http://www.google.com/').run(function(self) {
     self.exit();
 });