Support ICMS CSOSN 900.

Also, if the sale was emitted in the ECF, dont export the full icms details,
just the required information.

This is done so the shop don't have to pay the taxes twice - one for the
ECF, and another for the NFe.

Change-Id: Ibe6aa29b9aea90408cc6980c74a67f2b187f372c
Merge "Support ICMS CSOSN 900."