remove outdated php versions

Author: maennchen

.travis.yml

@@ -4,9 +4,6 @@ php:
   - nightly
   - 7.0
   - 5.6
-  - 5.5
-  - 5.4
-  - 5.3
 matrix:
   allow_failures:
     - php: hhvm

README.md

@@ -51,7 +51,7 @@ following URL: http://pablotron.org/?cid=1535
 
 ## Requirements
 
-  * PHP version 5.3 or newer.
+  * PHP version 5.6 or newer.
 
 ## Contributors
 Please take a look at the CONTRIBUTOR-README.md File.

composer.json

@@ -19,7 +19,7 @@
 		}
 	],
 	"require": {
-		"php": ">= 5.3",
+		"php": ">= 5.6",
 		"ext-mbstring": "*"
 	},
 	"require-dev": {