[Feature request] Double puppet mode

[w1r0x]

It should be cool to get matrix_user<->skype_user bound.

I see it in this way:

1. Matrix user invites skype bot to private room
2. Matrix user set his skype credentials by commands
3. Skype bot stores credentials for this matrix user
4. Skype bot starts to use this credentials to talk in skype as this matrix user

If user don't want to add his credentials skype bot should use old behaviour like in matrix-hacks/matrix-puppet-skype#16

[ledangtrung]

Wonderful suggestion! I think it may be the best setup design.