Release to luarocks

[zepinglee]

I received a request to release the citeproc-lua package to luarocks (zepinglee/citeproc-lua#35 (comment)) and it requireslua-uni-algos and unicode-data. Are you interested in uploading them to luarocks?

I've drafted a commit for luarocks in zepinglee@8f6774b. Since standard Lua finds packages differently from luatex (kpse), I've modified some paths. Note that the unicode-data directory is expected to be located in the root of lua-uni-algos during packing or somewhere else configured with copy_directories in .rockspec. The datafile is also used to load .txt files of unicode-data.