Created TLS Check Sample

- Created Sample to test TLSv1.2 support
- Updated Documentation
- Updated README

README.md

@@ -9,6 +9,11 @@ __Welcome to PayPal PHP SDK__. This repository contains PayPal's PHP SDK and sam
 
 > **Before starting to use the sdk, please be aware of the [existing issues and currently unavailable or upcoming features](https://github.com/paypal/rest-api-sdk-python/wiki/Existing-Issues-and-Unavailable%5CUpcoming-features) for the REST APIs. (which the sdks are based on)**
 
+## Please Note
+> **The [PCIv3.1 DSS (PDF)](https://www.pcisecuritystandards.org/documents/PCI_DSS_v3-1.pdf) mandates (p.46) that TLSv1.0 be retired from service by June 30, 2016. All organizations that handle credit card information are required to comply with this standard. As part of this obligation, PayPal is updating it's services to require TLSv1.2 for all HTTPS connections. [Click here](https://github.paypal.com/SDK-R/tls-update) for more information**
+
+> **If you have the SDK v1.6.2 or higher installed, you can easily test this by running the TLSCheck sample.**
+
 ## SDK Documentation
 
 [ Our PayPal-PHP-SDK Page ](http://paypal.github.io/PayPal-PHP-SDK/) includes all the documentation related to PHP SDK. Everything from SDK Wiki, to Sample Codes, to Releases. Here are few quick links to get you there faster.