Remove need for secure.enable_security (#7)

With changes in lua-matrix mod now works with only secure.trusted_mods

init.lua

@@ -8,7 +8,7 @@ local ie, req_ie = _G, minetest.request_insecure_environment
 if req_ie then ie = req_ie() end
 if not ie then
   error("The Matrix mod requires access to insecure functions in order "..
-    "to work. Please disable mod security. This will hopefully change.")
+    "to work. Please add matrix to secure.trusted_mods.")
 end
 
 ie.package.path =
@@ -29,6 +29,10 @@ local function eprintf(fmt, ...)
   minetest.log("info", fmt:format(...))
 end
 
+-- Temporarily set require so that LuaIRC can access it
+local old_require = require
+require = ie.require
+
 local client = require("matrix").client(matrix.config.server..":"..matrix.config.port)
 
 local start_ts = os.time() * 1000
@@ -139,3 +143,6 @@ function matrix.say(message)
     end
   end
 end
+
+-- Restore old (safe) functions
+require = old_require