gamecake-zip

We need to be able to load zips from memory, not the filesystem so this
is a slightly modified version of luazip with that functionality added.

See libs/lua_zip/readme.md in the gamecake repo
https://github.com/xriss/gamecake/blob/master/libs/lua_zip/

# gamecake-zip

- v0.9
- initial rocks release.

Lua code documentation auto built from source comments can be found at
https://xriss.github.io/gamecake/docs/

modified version of luazip http://www.keplerproject.org/luazip