Menu breaks when opts.extra is not set

[linclark]

I was trying out the master branch of makemehapi and found that selecting any of the menu options resulted in this error:

/usr/local/lib/node_modules/makemehapi/node_modules/workshopper/menu.js:63
    if (opts.extras.indexOf(name.toLowerCase()) != -1)
                    ^
TypeError: Cannot call method 'indexOf' of undefined

This could just be a bug in makemehapi, but since menu.js contained a different conditional at line 41 which checked for opts.extras before acting on it, I figured that opts.extras shouldn't be assumed.

Feel free to close out if I'm wrong.

[rvagg]

you're absolutely right @linclark, a late addition not properly tested. thanks for picking it up and the PR!