Add BowerPHP a PHP implementation of Bower

Add link for BowerPHP A package manager for the web.  A PHP implementation of Bower

README.md

 * [Munee](https://github.com/meenie/munee) - An asset optimiser library.
 * [Pipe](https://github.com/CHH/pipe) - Another asset manager pipeline library.
 * [Puli](https://github.com/puli/repository) - A library for determining assets absolute paths.
+* [BowerPHP](https://bowerphp.org/) - A PHP implementation of Bower. A package manager for the web
 
 ## Geolocation
 *Libraries for geocoding addresses and working with latitudes and longitudes.*