Here is a mostly exhaustive list of the changes:
o Removes the SCRIPT_ENGINE_* status defines and replaces the
instances with regular boolean integer returns or changes the
procedure to return void. The latter case is better generally because
the caller ignores any status return (e.g. nmap.cc calling open_nse)
and/or the procedure raises a fatal error when unsuccessful.
o Moves the SCRIPT_ENGINE_LUA_DIR and the like to the nse_main.h header file.
o Removes the use of the SCRIPT_ENGINE_TRY (there was only one left)
and thus changes the call to l_dnet_open to a void function called
directly by luaopen_nsock (in nse_nsock.cc) instead of luaopen_nmap
(in nse_nmaplib.cc). I felt moving the function was also an
appropriate (but somewhat unrelated to the intent of the patch) change
as opening the dnet metatable is very related to opening up the
nsock library. This confines errors in opening the nsock library, including
opening the dnet metatable, to the call to luaopen_nsock.
o The FILES and DIRS defines are moved in to nse_fs.h where they are
more appropriate and localalized.
Moved the includes for Lua headers to the .cc files so they are
not needlessly, repeatedly included.
Similarly, moved some standard headers to the .cc files and reorganized
includes to be uniform for all nse_* source files.
Fixed whitespace (removed tabs).
