Update timeout script-args to use standard timespec

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)

scripts/mysql-enum.nse

@@ -35,6 +35,8 @@ http://seclists.org/fulldisclosure/2012/Dec/9
 -- |     test_mysql:<empty> - Valid credentials
 -- |   Statistics
 -- |_    Performed 11 guesses in 1 seconds, average tps: 11
+--
+-- @args mysql-enum.timeout socket timeout for connecting to MySQL (default 5s)
 
 author = "Aleksandar Nikolic"
 license = "Same as Nmap--See http://nmap.org/book/man-legal.html"
@@ -42,7 +44,8 @@ categories = {"intrusive", "brute"}
 
 portrule = shortport.port_or_service(3306, "mysql")
 
-local arg_timeout = stdnse.get_script_args(SCRIPT_NAME .. ".timeout") or 5
+local arg_timeout = stdnse.parse_timespec(stdnse.get_script_args(SCRIPT_NAME .. ".timeout"))
+arg_timeout = (arg_timeout or 5) * 1000
 
 Driver = {
 
@@ -58,7 +61,7 @@ Driver = {
 	connect = function( self )
 		self.socket = nmap.new_socket()
 		local status, err = self.socket:connect(self.host, self.port)
-		self.socket:set_timeout(tonumber(arg_timeout) * 1000)
+		self.socket:set_timeout(arg_timeout)
 		if(not(status)) then
 			return false, brute.Error:new( "Couldn't connect to host: " .. err )
 		end