Add Safe.

README.md

 * [Prooph Service Bus](https://github.com/prooph/service-bus) - Lightweight message bus supporting CQRS and Micro Services
 * [RMT](https://github.com/liip/RMT) - A library for versioning and releasing software.
 * [sabre/vobject](https://github.com/sabre-io/vobject) - A library for parsing VCard and iCalendar objects.
+* [Safe](https://github.com/thecodingmachine/safe) - All PHP functions, rewritten to throw exceptions instead of returning false.
 * [Slimdump](https://github.com/webfactory/slimdump) - An easy dumper tool for MySQL.
 * [Spork](https://github.com/kriswallsmith/spork) - A process forking library.
 * [SuperClosure](https://github.com/jeremeamia/super_closure) - A library that allows Closures to be serialized.