Support Multiple Taxes

[mathamel]

We have some use case where 2 taxes apply to a taxe zone

• Canada / Quebec : TPS 5% and TVQ 9.975%

They both need to be shown on invoice and shown separately, they cannot be merged.

Product 10.00$
TPS (5%) : 0.50$
TVQ(9.975%) : 1.00$ (0.9975$ round up)
Total: 11.50$ (round up 11.4975$)

Currently, tax only select 1 that fit the product taxe category + taxe zone;