About the lua documentation

[June Zhang <jhzhangdev@...>]

Currently every lua version has its own documentation, and they are independent. I wonder could we merge all the documentation into one? After doing that we can: 1) add availability info into every API (such as available 5.2+); 2) give obsolescence info to some old API and explain the reason. I think doing this can makes our document more instructive and coherent. Thanks.