Bump version from 1.6.1 to 2.1.0

@drequivalent hi, actually I usually stay in Japanese instance so. Sorry about that.

@drequivalent Glad to hear that, anything new with you recently?

@ernix Not very much yet, actually, aside from grandma being dead. Also, got one more cat in my house.

suu @ernix

@drequivalent I'm so sorry for your loss