Added strict library for libraries (and scripts). The module function is

replaced so that all NSE modules will have strict declared global checking at
runtime. This should catch most developer errors early. Please see [1] for
further reference into the problem.

[1] http://seclists.org/nmap-dev/2009/q3/0070.html

nse_main.lua

@@ -88,6 +88,8 @@ do -- Append the nselib directory to the Lua search path
   package.path = package.path..";"..path.."?.lua";
 end
 
+(require "strict")() -- strict global checking
+
 -- NSE_YIELD_VALUE
 -- This is the table C uses to yield a thread with a unique value to
 -- differentiate between yields initiated by NSE or regular coroutine yields.