Removed intel.lua.

(This was accidentally revived. We want to do that, but it needs a
little maintenance first.)
config.lua: Comments.
link.lua: Small fixes.
Migrated designs/basic to new app interface.
Migrated apps.vhost_apps to new app interface.
Migrated apps.rate_limiter to new app interface.
Migrated apps.ipv6 to new app interface.
Migrated apps.pcap to new app interface.
Migrated app.intel_app to new app interface.
asm.lua fixes.
app.lua: Debugging.
Migrated apps.basic.basic_apps to new app interface.