Update esper dependency version.

Author: kbirk

Diff for: public/bower.json

@@ -6,7 +6,7 @@
     "async": "1.4.2",
     "d3": "3.5.6",
     "draggabilly": "1.2.4",
-    "esper": "0.4.0",
+    "esper": "0.4.1",
     "jquery": "2.1.4",
     "leaflet": "0.7.7",
     "lodash": "3.10.1",

Diff for: public/javascripts/layers/webgloverlay.js

@@ -58,13 +58,7 @@
             var self = this,
                 shadersDone = $.Deferred(),
                 buffersDone = $.Deferred(),
-                gl;
-            // overwrite alert temporarily
-            var alert = window.alert;
-            window.alert = function() {};
-            gl = this._gl = esper.WebGLContext.get( this._canvas );
-            // restore alert
-            window.alert = alert;
+                gl = this._gl = esper.WebGLContext.get( this._canvas );
             // handle missing context
             if ( !gl ) {
                 return;