Stringify all value of data object.

Author: Denis Rechkunov

lib/UHRBase.js

@@ -302,6 +302,12 @@ UHRBase.prototype._getDataToSend = function (headers, data) {
 		};
 	}
 
+	Object.keys(data)
+		.forEach(function (key) {
+			data[key] = data[key] !== undefined ?
+				String(data[key]) : data[key];
+		});
+
 	if (contentType === UHRBase.TYPES.JSON) {
 		return {
 			headers: headers,