Uniform file path & support copy files to release zip

[xiejiangzhi]

[xiejiangzhi]

Since I haven't learned the Rust language, the code is basically learned by google or your source code. Originally wanted to add a feature that specifies love download url, but I'm too slow to write it, so it's gone.

[xiejiangzhi]

This copy feature can fuse all code to love.exe and copy our assets(image, audio, font, ext) to outside,

lfs = love.filesystem
if lfs.isFused then
  lfs.mount(lfs.getSourceBaseDirectory(), '', true)
end