Update Readme and add gitignore

Author: Vincent Thiery

.gitignore

@@ -0,0 +1 @@
+build/

README.md

@@ -9,7 +9,7 @@ The client allows:
 ## Usage
 A simple example of how to use the client:
 
-```
+```cpp
 #include "StatsdClient.hpp"
 using namespace Statsd;