No typescript typings

[G-Rath]

I'd love to use this library with typescript.

I've written my own typings for the time being, but would be happy to out in getting all the micromatch libraries typed.

However since right now I don't have the time, rather than make PRs I've made this issue, in the hopes of kicking off the typing process, and to make my typings available for those wantings to use them :)

[jonschlinkert]

That would be great! Thank you!

[larshp]

suggestion added in https://github.com/micromatch/picomatch/pull/53