Patch to libraries that were inappropriately using globals.

Often two (or more) scripts using the same library would
overwrite the globals each was using. This would result
in (at best) an error or (at worst) a deadlock.

The patch changes the global accesses to local.

nselib/datafiles.lua

@@ -183,6 +183,7 @@ function parse_lines(lines, data_struct)
       elseif type(value) == "string" or type(value) == "function" then
         ret = get_array( lines, value )
       elseif type(value) == "table" then
+        local _
         _, ret[index] = parse_lines( lines, value )
       else
         -- TEMP