[Feature Request] Would be nice to have support for less.

[adoy]

We recently migrated from icon-font-generator to your tool and it's pretty nice. Only issue we had is that our hbs template is generating a less file format, but there is no way to generate a .less file. We had to generate a "css" file using a custom template that generate less and then rename the file with the proper extension.

It would be nice to have a mechanism to control the output filename and/or to generate any file format you want.