Fixes incompatibility with PhantomJS 1.9 Ghostdriver mode (fixes #594)

The core problem seems to be that PhantomJS 1.9 has problems with some lowercase headers.
request 2.49.0 is the latest version that works correctly in addition to setting
the Content-Type and Content-Length header with uppercase.

Relevant issues:

* PhantomJS issue: ariya/phantomjs#11421

lib/utils/RequestHandler.js

@@ -7,6 +7,7 @@
 var Q = require('q'),
     url = require('url'),
     request = require('request'),
+    merge = require('deepmerge'),
     errorCodes = require('./errorCodes'),
     ErrorHandler = require('./ErrorHandler'),
     packageDotJson  = require('../../package.json');
@@ -106,9 +107,13 @@ RequestHandler.prototype.createOptions = function(requestOptions, data) {
     };
 
     if (Object.keys(data).length > 0) {
-        newOptions.body = data;
+        var requestData = JSON.stringify(data);
+        newOptions.body = requestData;
         newOptions.method = 'POST';
-        newOptions.json = true;
+        newOptions.headers = merge(newOptions.headers, {
+            'Content-Type': 'application/json; charset=UTF-8',
+            'Content-Length': Buffer.byteLength(requestData, 'UTF-8')
+        });
     }
 
     return newOptions;

package.json

@@ -49,7 +49,7 @@
     "inquirer": "^0.8.5",
     "optimist": "^0.6.1",
     "q": "~1.3.0",
-    "request": "~2.55.0",
+    "request": "2.49.0",
     "rgb2hex": "~0.1.0",
     "supports-color": "^1.3.1",
     "url": "~0.10.3",