Issue Description

Receive the following error when checking out with Tax enabled

Client provided total price 28.979 for group with index 0, but actual total price is 28.978999999999996

Steps to Reproduce

I am not completely sure which of these are the critical steps but i can reproduce this error following these steps.

1. Reset database
2. Enable Stripe and Example Payment
3. Enable all Flat Rate shipping methods
4. Enable tax rate at 10% for the state of California
5. As an anonymous user add one red "Basic Reaction Product" to your cart (because the price is $19.99)
6. Checkout and choose "Flat Rate - Priority"
7. Checkout with either the Example or Stripe payment methods
8. Observe the error

Possible Solution

There's a rounding error happening somewhere. Tax is stored on the item at 1.999. Not sure if that's correct or not.

Versions

Reaction: 2.0.0-rc1

I hate making stuff critical that no one else has run into, but it seems like making something X.99 is probably as pretty common case for pricing.