Replacement of the NW2 library with lua based NW.

I think that its functionality is as similar to the original as possible. Tested both linux&windows. Created because of update 03.09.2019(issue Facepunch/garrysmod-issues#3978). Addons now work as before update.

Install:

Put sh_nw3.lua to autorun shared folder, i.e. addons/<any_addon_name>/autorun/sh_nw3.lua