Simplified skinned mesh model

To be correct, its skinned mesh with just one bone index for each vertex (one or more meshes → only one bone), but its very useful for minecraft like models, i currently upload 16 bones (matrices) at once, for all cases it`s enough to render model in one render call (typical model just 6 bones)
ps.
Also fixed sending position of existing users to new connected users and vice versa (before position sends only when moved)
as usual could be tested here:
http://stilker.sknt.ru:3001/