fix(Logger): logging level comparision

Before the fix the logger would not log when the log level
equals it's level.

lib/Logger.js

@@ -76,7 +76,7 @@ function getCallerInfo() {
 function log() {
     var logger = arguments[0], level = arguments[1],
         args = Array.prototype.slice.call(arguments, 2);
-    if(levels[level] <= logger.level) {
+    if(levels[level] < logger.level) {
         return;
     }