By default install composer

By default the cookbook should be stable and not to be in the edge
update spec
Merge branch 'patch-2' of github.com:Maks3w/composer into Maks3w-patch-2
Tweak spec
Fix for Rubocop
Fix for Rubocop
Drop Ubuntu 12.04LTS due to php-cookbook dependency failing to install without a prior apt-get update
Version bump