Missing license

[yzhou216]

Could you please add a LICENSE file to the project? Thanks!

[buyukakyuz]

Thanks for the issue. I will. I haven't decided which license to use yet.

[yzhou216]

Thanks for the issue. I will. I haven't decided which license to use yet.

LGPL-3.0-or-later is a good choice for parlance IMO, but it's up to you.

Another choice is to dual license this under LGPL-3.0-or-later OR MPL-2.0.