Changes fall into these categories:
1. Avoid pathological string building. Loops over x = x .. "foo" can
become very slow. Instead, use strbuf.lua, table.concat, or just one
continuous concatenation; a = x .. y .. z is one operation, better than
a = x .. y; a = a .. z
2. Use hex-escaped strings instead of string.char. I find this more
readable in many cases, and it avoids a table lookup and function call.
3. Don't duplicate code. A few libraries and scripts had re-implemented
stdnse.generate_random_string or openssl.rand_bytes.
Many scripts were documented as using timespecs (10s, 5000ms, etc) for
timeout script-args, but one 1 or 2 actually did. Now all timeout
script-args will accept timespecs, except those which took a number of
milliseconds, which remain unchanged.
Also fixed some documentation issues (missing script name in arg
description, missing nsedoc for args, etc)
action() time when executed unprivileged.
Removed the check which was performed by broadcast-dhcp-discover.nse in its
action() function, so that users can force execution if desired.