Change name convention

Maybe you don't want to use prefixes and postfixes to class names of maxmertkit. For example instead of -btn use w-btn or jsut btn.

To do that edit file sass/common/_convention.sass. You will find prefixes and postfixes for all maxmertkit elements there.

For example to use for widgets prefix w-, just add

$pref-widget: "w-"
$post-widget: ""