auth_token: Various updates, see below. * Defer to usermanager when testing the password * Because of this, don't assume the realm is available when verifying the token * Fix linting errors By using the `usermanager`, other modules can now ask the user manager to verify token credentials.

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.