Missing sub method for Matrix

[tdimeco]

Hi,

I realized there is no methods to substract two matrix. Maybe it's related to Accelerate, that does not provide any method to substract matrix?

Maybe it makes sense to add a sub method and a - operator for matrix, that do something like :

add(lhs, mul(-1.0, rhs))

What do you think about this?

[rmzr7]

I added a sub method in this fork https://github.com/remzr7/Surge

[plm75]

It would be nice if that was added directly here or if @remzr7 could make a pull request maybe ?

[alejandro-isaza]

It's in