Feature request: pull_array and pull_vector

[haesleinhuepf]

I wrote now multiple times this code:

int size ...;
std::vector<float> result(size);
gpu_result.read(result);

And I'm wondering if it could be put into a pull_vector function, which would make my life easier:

std::vector<float> result = cle::pull_vector(gpu_result);

[StRigaud]

The pull_vector would need to be templated. Like I said in your PR, the output vector template type must match the gpu array type.

I did something like that if you look in the memory.hpp functions, but I stopped using them because it simply save 1 line of code and this type of function would better fit a user API which CLIc is not.