Switch from Vector{Vect3D{Float32}} to plain array

Vector{Vect3D{Float32}} were not at all aligned in memory,
causing a major slowdown (~10 to 100) in all access.

The Array3D type is a wrapper type around Array which
should be faster.
Fix deprecation warning
Add inplace version of methods

This remove lot of temporary allocations (RDF test from 1.9G to 100M)
and allow to get the same speed as before \o/.
[doc] Use @doc macro instead of comments