mod_delegation: update to XEP-0355 v0.5 - namespace bump to "urn:xmpp:delegation:2" - disco remaining infos now uses the XEP defined "urn:xmpp:delegation:2:bare:disco#info:*" namespace - complemeted disco remaining infos implementation for requests made on nodes not already managed by the server - bare JID disco items now uses the XEP defined "urn:xmpp:delegation:2:bare:disco#items:*'" namespace

This module logs events where more than a certain amount of CPU time was
spent.

``` lua
log_cpu_threshold = 0.01 -- in seconds, so this is 10 milliseconds
```

Uses the Lua
[`os.clock()`](http://www.lua.org/manual/5.2/manual.html#pdf-os.clock)
function to estimate CPU usage.