Many users of the SSL build of mosquitto need the passwd utility for
managing keys.

Fixes github issue #1909

Signed-off-by: Karl Palsson <karlp@remake.is>

Of particular note, this adds optional support for websockets. This
defaults to enabled, as it's the biggest new feature in this release.
A config item is provided to disable it for manual use.

Full release notes: http://mosquitto.org/2015/02/version-1-4-released/

This also remove some build workarounds that are no longer required for
newer versions of mosquitto.

Signed-off-by: Karl Palsson <karlp@remake.is>