yo style-prototype:pattern creates layout classes with underscore

[peteainsworth]

Scaffolding a layout pattern with yo style-prototype:pattern creates a layout with a class that doesn't begin with an underscore. Minor problem obvious because you can just add one but thought I'd let you know. Adding the underscore as the pattern name results in:

create layouts/-foobar/-foobar.html
create js/layouts/-foobar/-foobar.js
create sass/partials/layouts/_-foobar.scss
create sass/partials/layouts/-foobar/_extends.scss
create sass/partials/layouts/-foobar/_mixins.scss
create sass/partials/layouts/-foobar/_variables.scss