Upgrade to lodash v4 (#660)

* npm install lodash-2

Someone handily published a lodash-2 v4.17.4 - it is exactly the same as lodash v4.17.4, so it is safe to use during the migration.

* use lodash-2 in tests

* update tests to split utils vs lodash

* remove Utils.nextTick usage

Utils.nextTick with a single argument is the same as process.nextTick

* lowercase utils

Because it seems that this is the coding style in this repo

* upgrade lodash in grunt/*

* keep lodash-2 as a dev dep for now

* use lodash-2 in scripts

* use snakeCase from utils

It was a mistake in my previous commit to not update this usage

* fix naming gruntUtils vs utils

As all three - gruntUtils, utils and lodash (_) are getting passed into templates, it makes sense to keep the naming consistent

* fix naming gruntUtils vs utils

As all three - gruntUtils, utils and lodash (_) are getting passed into templates, it makes sense to keep the naming consistent

* split utils vs lodash in scripts/generate

Also use lodash-2 where it is easy to do so

* use utils.get until lodash upgrade

* remove lodash.isempty; lodash-2 now used in prod (in src/lib/apis/ code)

* unbundle lodash from utils

* upgrade to lodash 4

* remove lodash.get and lodash.trimEnd

* clean out unused code

* clean out unused code

* fix a breaking change listed under "notable changes" rather than under "breaking changes"...

test/mocks/browser_http.js

@@ -227,7 +227,7 @@ MockHttpRequest.prototype = {
       }
       //TODO title case header
       r += header + ': ' + this.responseHeaders[header] + '\r\n';
-    }, this);
+    }.bind(this));
     return r;
   },
 
@@ -355,7 +355,7 @@ MockHttpRequest.prototype = {
     this.error = true;
     _.each(this.requestHeaders, function (header) {
       delete this.requestHeaders[header];
-    }, this);
+    }.bind(this));
 
     this.readyState = this.DONE;
     if (!this.async) {