Update readme.md
Update readme.md

Changing the Composer file example to allow sub-versions. This will get people around issues when upgrading to Laravel 4.2.
Stayallive/PHP-Vars-To-Js-Transformer,lotestudio/PHP-Vars-To-Js-Transformer,laracasts/PHP-Vars-To-Js-Transformer,loshmis/PHP-Vars-To-Js-Transformer,richardwyke/PHP-Vars-To-Js-Transformer,SelimSalihovic/PHP-Vars-To-Js-Transformer