Update release notes

Author: ayoung

releasenotes.markdown

@@ -5,16 +5,16 @@
 * Fixed Windows Phone and Silverlight to use culture when calling Convert.ChangeType() (thanks trydis)
 * Added support for non-standard HTTP methods (thanks jhoerr)  
   New API methods include:
-  * IRestClient.ExecuteAsyncGet()
-  * IRestClient.ExecuteAsyncPost()
-  * IRestClient.ExecuteAsyncGet<T>()
-  * IRestClient.ExecuteAsyncPost<T>()
+  * `IRestClient.ExecuteAsyncGet()`
+  * `IRestClient.ExecuteAsyncPost()`
+  * `IRestClient.ExecuteAsyncGet<T>()`
+  * `IRestClient.ExecuteAsyncPost<T>()`
 
   See [groups discussion](https://groups.google.com/forum/?fromgroups=#!topic/restsharp/FCLGE5By7AU) for more info
 
 * Resolved an xAuth support issue in the OAuth1Authenticator (thanks artema)
 * Change AddDefaultParameter methods to be extension methods (thanks haacked)  
-  Added RestClientExtensions.AddDefaultParameter() with 4 overloads. See pull request [#311](https://github.com/restsharp/RestSharp/pull/311) for more info
+  Added `RestClientExtensions.AddDefaultParameter()` with 4 overloads. See pull request [#311](https://github.com/restsharp/RestSharp/pull/311) for more info
 
 * Adding support for deserializing enums from integer representations (thanks dontjee)