recursivecopy! for sparse inputs

This currently does not work:

```julia
using DiffEqBase,OrdinaryDiffEq
function fun1(t,u,du)
    A = sparse([1,2],[2,1],[-1.0im,-1.0im])
    A_mul_B!(du,A,u)
end
p = ODEProblem(fun1,sparsevec(complex.([1.0,0.0])),(0.0,3pi));
r = solve(p,Vern8(),adaptive=false,dt=3pi/100);
```