Support custom capitalization for task name

[lazd]

We currently have something like this in tasks/assets/README.tmpl.md:

## {%= _.capitalize(name) %} task

This causes output that doesn't necessarily match what's expected. In my use case for grunt-domly, DOMly comes out at Domly, which doesn't match the branding for the project.

Maybe we can allow the files to be named as DOMly-examples.md etc to avoid this?