Add the missing parsebody function to mod_lua, for parsing POST data.
PR 53064.

- Define LUA_COMPAT_ALL so mod_lua will be compatible with Lua 5.2
- Add an optional integer argument for parsebody, specifying the maximum size of POST that will be accepted.
Submitted by: humbedooh
Reviewed/backported by: jim


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1365539 13f79535-47bb-0310-9956-ffa450edef68