Added administration.lua.

Adds self-hosted, single-realm administrative functions to otouto.
Check out the README for a detailed description.

Also added msg.from.name, which is msg.from.first_name + msg.from.last_name (if it
exists), because I'm too lazy to build it each time.
Fixed a crash-causing bug (ironically) in the handle_exception() function.

config.lua

@@ -12,6 +12,7 @@ return {
 	time_offset = 0,
 	lang = 'en',
 	antisquig = false,
+	-- If you change this, make sure you also modify launch-tg.sh.
 	cli_port = 4567,
 	admin = 00000000,
 	admin_name = 'John Smith',