Merge pull request #26 from kalimatas/fix-phpunit-version

Require phpunit: ~4.8

Author: Alexander Guz

composer.json

@@ -22,7 +22,7 @@
 		"php": ">= 5.3"
 	},
 	"require-dev": {
-		"phpunit/phpunit": "*"
+		"phpunit/phpunit": "~4.8"
 	},
 	"autoload": {
 		"psr-4": {