Any C function can receive maxinteger as an integer argument, and
therefore cannot increment it without some care (e.g., doing unsigned
arithmetic as the core does).

Comments and small improvements in the manual.

More uses of macros 'likely'/'unlikely' (renamed to
'l_likely'/'l_unlikely'), both in range (extended to the
libraries) and in scope (extended to hooks, stack growth).

Several small changes from feedback on 5.4 alhpa rc1 (warnings,
typos in the manual, and the like)

- 'luaL_setfuncs' avoids creating closures for placeholders.
- Fixed some warnings about unused values in comma expressions.
- Comments.

Checks of the form '1 <= x && x <= M' were rewritten in the form
'(unsigned)x - 1 < (unsigned)M', which is usually more efficient.
(Other similar checks have similar translations.) Although
some compilers do these optimizations, that does not happen
for all compilers or all cases.

Version numbers and dates (mostly wrong) from RCS keyword strings
removed from all source files; only the file name are kept.