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.

(name too common, may collide when doing 'onelua.c')

(still no metamethods, no raw verssions)

given as an explicit extra argument