Added uninstall method. Installers now delete folder with package installed via composer/installers. Closes GH-84.
Added uninstall method. Installers now delete folder with package installed via composer/installers. Closes GH-84.

blesta/installers,composer/installers,bluematt/composer-installers,shipci/installers,KennisMeester/installers,ribrit/installers,c9s/installers,micaherne/installers,corneltek/installers,dedalozzo/installers,kidaa/installers,QafooGalaxy/installer,buildsample/installers,potherca-contrib/installers,beaver-dev/feather-installers,monofone/ansible-installer