option to include 'module exports' instead of react component for htmltojsx command line

[solugebefola]

Perhaps a -e to add module.exports? I modded the cli.js in order to be able to require the generated file and insert into another component's render function directly.

[Daniel15]

Perhaps it should use ES2015 module syntax, since module.exports syntax will disappear eventually as people standardise on ES2015 modules instead.

[solugebefola]

That's a good idea, I will modify the PR soon