No point shutting down nicely if the connection has failed: exit
immediately and print out an error.
The error is the same whether the connection has failed due to a DNS
lookup, TCP connection or authentication failure. Running in debug mode
can show the reason for failure. libstrophe has an enum indicating the
connection state; maybe this can be used for better error reporting.
Add a ID per message. Seems to fix the duplicate messages seen with MUCs
on the Conversations android client whenever the network is switched
(e.g., from wifi to cell).
Introduce a dependency on Linux's libuuid which introduces portability
issues. However, it should be simple to add support for the BSD UUID
interface.
libuuid was used because it is a fast and simple way of generating
a unique id. Realistically, the ID only needs to be unique within
the MUC and so could probably be replaced with an sprintf() combining
time of day, PID and a random number.
Force exiting on nick conflicts. xmppipe could generate a unique resource
(e.g., xmppipe-<pid>) but it prevents accidentally having two instances
running in a room.
