require 5.4 and add JsonSerializable -on branch - prep for pr

.travis.yml

@@ -1,7 +1,6 @@
 language: php
 
 php:
-  - 5.3
   - 5.4
   - 5.5
   - 5.6

README.md

@@ -9,7 +9,7 @@
 
 ## About
 
-Rhumsaa\Uuid is a PHP 5.3+ library for generating and working with
+Rhumsaa\Uuid is a PHP 5.4+ library for generating and working with
 [RFC 4122][rfc4122] version 1, 3, 4, and 5 universally unique identifiers (UUID).
 
 From [Wikipedia](http://en.wikipedia.org/wiki/Universally_unique_identifier):

composer.json

@@ -1,6 +1,6 @@
 {
     "name": "rhumsaa/uuid",
-    "description": "A PHP 5.3+ library for generating RFC 4122 version 1, 3, 4, and 5 universally unique identifiers (UUID).",
+    "description": "A PHP 5.4+ library for generating RFC 4122 version 1, 3, 4, and 5 universally unique identifiers (UUID).",
     "type": "library",
     "keywords": ["uuid", "identifier", "guid"],
     "homepage": "https://github.com/ramsey/uuid",