Remove PHP 5.3 support.

5.3 is now [EOL] and there is no reason for us to continue to support
this version from this moment on.  Users needing PHP 5.3 support can use
the previous version.

[EOL]: http://php.net/archive/2014.php#id2014-08-14-1

Author: Spencer Rinehart

.travis.yml

@@ -3,7 +3,6 @@ php:
   - 5.6
   - 5.5
   - 5.4
-  - 5.3
   - hhvm
 install: composer install
 script: ./vendor/bin/phpunit

README.md

@@ -10,7 +10,7 @@ A PHP library for memoizing repeated function calls.
 [![License](http://img.shields.io/packagist/l/dominionenterprises/memoize.svg?style=flat)](https://packagist.org/packages/dominionenterprises/memoize)
 
 ## Requirements
-This library requires PHP 5.3, or newer.
+This library requires PHP 5.4, or newer.
 
 ## Installation
 This package uses [composer](https://getcomposer.org) so you can just add

composer.json

@@ -11,7 +11,7 @@
     ],
     "license": "MIT",
     "require": {
-        "php": ">=5.3.2"
+        "php": "~5.4"
     },
     "require-dev": {
         "predis/predis": "~1.0",