Added php 5.6 for travis
Added php 5.6 for travis

Crinsane/LaravelShoppingcart,tinywitch/LaravelShoppingcart,HaelioMarcio/LaravelShoppingcart,andradedev/LaravelShoppingcart,kingpabel/LaravelShoppingcart,junkystu/LaravelShoppingcart,InfiniteDevelopment/LaravelShoppingcart,janusnic/LaravelShoppingcart,martindevnow/LaravelShoppingcart,mateusjatenee/LaravelShoppingcart-1,janneison/LaravelShoppingcart,yufi113/LaravelShoppingcart,rikw22/LaravelShoppingcart,IvanBernatovic/LaravelShoppingcart,darthsoup/laravel-shoppingcart,Laraverse/Cart