Application name for 'readline' is "lua", not "Lua"

New release number, updated copyright year

'lua.h' back to redundancy in version definitions

Several tools inspect 'lua.h' to extract version information, and
they assume the file will have some specific format.

"Emergency" new version 5.4.6

'lua_resetthread' is back to its original signature, to avoid
incompatibilities in the ABI between releases of the same version.
New function 'lua_closethread' added with the "correct" signature.

Details

Typos in comments and details in the manual.

Explanation of borders in the manual

The explanation includes the limit case of maxinteger being a border.
It also avoids the term "natural", which might include large floats
with natural values.

Added option LUA_NOBUILTIN

This option allows external code to avoid the use of gcc builtin macro
'__builtin_expect' in the Lua API.

Optimization for 'n^2'

Squares are much more common than other exponentiations, and 'n*n' is
much more efficient than 'pow'.

Merge branch 'master' of https://github.com/lua/lua

Adding file README.md to local repository.

Fixed bug of long strings in binary chunks

When "undumping" a long string, the function 'LoadVector' can call the
reader function, which can run the garbage collector, which can collect
the string being read. So, the string must be anchored during the call
to 'LoadVector'. (This commit also fixes the identation in 'l_alloc'.)