[reSIProcate] Changes to resiprocate/dum interfaces

[Fischl jason <jason.fischl@xxxxxxxxx>]

In the latest work session we've done some refactoring of resiprocate
to support having multiple Transaction Users (TU) in a resip-based
application. There are a few implications and interface changes.

- DialogUsageManager constructor now must take a SipStack&
- UserProfile::setDigestCredential no longer takes an aor argument
since the UserProfile is already bound to an aor
- Applications can have multiple TransactionUsers (e.g.
DialogUsageManager or Proxy). Each TU needs to register with the
TransactionUserSelector using this interface
SipStack::registerTransactionUser(TransactionUser& tu). The
DialogUsageManager will do this for you in its constructor.

Keep in mind that this means your application needs to make a SipStack
and pass it into the DialogUsageManager. If you are creating multiple
TUs you should share the same SipStack with each of these.

Each incoming message is  matched against the list of TUs that have
been registered with the SipStack.  More to follow on this topic.

As a convenience, there are two classes which help you run your
DialogUsageManager and/or SipStack in their own threads. For example,
if you were writing a presence server or registrar, you could use the
following approach:

SipStack stack;
StackThread stackThread(stack);

DialogUsageManager dum(stack);
DumThread dumThread(dum);

stackThread.run();
dumThread.run();
stackThread.join();
dumThread.join();


If you are implementing a useragent such as a softphone that might
have a gui component running the same thread as the dum, use this
approach instead:

SipStack stack;
StackThread stackThread(stack);

DialogUsageManager dum(stack);
stackThread.run();

while (!shutdown) // some local variable
{
    while (dum.process());
    // do your gui stuff here. 
}
stackThread.join();


You can also run without a StackThread if you'd like everything to run
in a single thread.
SipStack stack;
DialogUsageManager dum(stack);
while (!shutdown) // some local variable
{
      try
      {
         resip::FdSet fdset;
         buildFdSet(fdset);
         stack.buildFdSet(fdset);
         int ret = fdset.selectMilliSeconds(stack.getTimeTillNextProcessMS());
         if (ret >= 0)
         {
            stack.process(fdset);
         }
      }
      catch (BaseException& e)
      {
         InfoLog (<< "Unhandled exception: " << e);
      }

    while (dum.process());
    // do your gui stuff here. 
}

There will be more to follow on how to use the new Proxy TU - as well
as how to use the Proxy TU in conjunction with one or more User Agent
TUs.