some example program unique_ptr's need to be float[], not float

[eyalroz]

In the vectorAdd.cu example program, we have 3 lines looking like:

auto h_A = std::unique_ptr<float>(new float[numElements]);

... but it should actually be a unique_ptr<float[]>, an array unique_ptr. We also have this in streamOrderedAllocation.cu. Other example programs (including vectorAdd variants) already have this fixed.