Balancing T-gates and Toffoli gates in the final cost

[PabloAMC]

Explanation

Some costs like Toffolis or controlled swaps are more naturally performed using Toffoli gates, while others (eg rotations) are more suitable for T-gates. This does not mean that Clifford+either of them is not universal, but it may not be the most efficient. Thus, while right now all costs are expressed as T-gates, being able to balance both in the final cost function would be beneficial.

Also, probably we should take into account better methods to count the Toffoli or T-gate synthesis cost, which I am not sure is right at the moment.

What changes are required.

• Sort each kind of subroutine in utils in Toffoli or T gate, and change their cost correspondingly.
• Change each method cost to take into account both costs.
• Find a way to take into account the synthesis cost of both T-gates and Toffolis.