create resources folder during project_setup, and link with emscripten
--embed-file complained b/c the directory was empty, so I added
resources/placeholder.txt
I tested project_setup.sh (but not project_setup.ps1) -- the emscripten
build works
also, s/std.builtin.Mode/std.builtin.OptimizeMode
(std.builtin.Mode's source says: "///Deprecated; use OptimizeMode.")