Version 1.3.0 - major changes, additions, fixes

+ Added feature to handle recursive tables - even absolutely weird cases
like `local a, b = {}, {}; a[b] = a; b[a] = b`;
> Added code to check if keys are integers - previously the table
serialization function would swallow floating-point keys from tables if
they were between 1 and the length of the table's array part in value;
> Fixed version number - the minor version digit was misplaced.

The Garry's Mod-specific version is now merged into the standard version
with minor performance cost, but greatly eases further development.