Update, Enable Sponsorship

[Angry_Panda_ROAR]

Tested now

If an user pays with sponsored fees:
i.e. pays 0.003 XYZ (-0.003 XYZ)

The XYZ token issuer:
pays 0.001 Waves (-0.001 Waves)
receives 0.003 XYZ (+0.003 XYZ)