Updated User Agent & More Samples for Billing Plans

- Fixed versioning in User Agent.
- Updated Billing Plan sample to update Payment definitions
- Docs & Tests

sample/doc/payments/AuthorizePayment.html

@@ -38,7 +38,7 @@ to correct setting. In this case, it would be &#39;authorize&#39;</p></div></div
 
 <span class="hljs-variable">$amount</span> = <span class="hljs-keyword">new</span> Amount();
 <span class="hljs-variable">$amount</span>-&gt;setCurrency(<span class="hljs-string">"USD"</span>)
-    -&gt;setTotal(<span class="hljs-string">"1.00"</span>);
+    -&gt;setTotal(<span class="hljs-number">1</span>);
 
 <span class="hljs-variable">$transaction</span> = <span class="hljs-keyword">new</span> Transaction();
 <span class="hljs-variable">$transaction</span>-&gt;setAmount(<span class="hljs-variable">$amount</span>)