docs/libraries-and-tools: Update libraries-and-tools.md with etcdcpp

Add a c++ language binding for API version 2.2.0

Documentation/libraries-and-tools.md

@@ -53,6 +53,7 @@
 
 **C++ libraries**
 - [edwardcapriolo/etcdcpp](https://github.com/edwardcapriolo/etcdcpp) - Supports v2
+- [suryanathan/etcdcpp](https://github.com/suryanathan/etcdcpp) - Supports v2 (with waits)
 
 **Clojure libraries**