new functionalities for transient reduced basis

> Yeah, it's not needed, but why not include the 0.0 anyway?

Why not include the 0.0 every time you `resize` a vector then?  Actually I don't mind it that much, but seeing the second argument immediately makes me have to go look up the definition of `resize` with two arguments, to make sure that it doesn't set every entry in the resized vector to that value...