Update the blacklist for unrequire

When testing the unrequire tool on OpenOS 1.6.1, I found that it could unload things that broke OpenOS, so I used a process of elimination to find out what not to unload. It seems to work.

Author: skyem123

unrequire.lua

@@ -9,6 +9,12 @@ local blacklist = {
 	["shell"] = true,
 	["package"] = true,
 	["process"] = true,
+	["unicode"] = true,
+	["computer"] = true,
+	["component"] = true,
+	["_G"] = true,
+	["term"] = true,
+	["keyboard"] = true
 }
 
 local function errprint(msg)