Added basic ZeroConf interface.

- registers oneself, browses and resolves services.
 - Lots still TODO:
	- parse TxtRecords.
	- Track peers.
	- feedback to libretroshare
	- etc, etc.
Enabled ZeroConf in libretroshare.pro & rsinit.cc. Compiles and runs on OSX.
Added RelayHandler to Dht, to enable external control of Relays.
Marked pqiAssist Interface for changes... will be revamped with ZeroConf.



git-svn-id: http://svn.code.sf.net/p/retroshare/code/branches/v0.5-dhtmods@4727 b45a01b8-16f6-495d-af2f-9b41ad6348cc

libretroshare/src/zeroconf/NOTES.txt

@@ -0,0 +1,33 @@
+
+The Code in this directory refers to APPLEs ZeroConf Library.
+
+We have two classes: p3ZeroConf & p3ZeroConfNat
+The first provides ZeroConf(Bonjour) discovery services.
+The second provides UPnP & NAT-PMP Nat Port Forwarding.
+
+OSX
+----------------
+Both should compile with no problems under OSX.
+Both will be compiled by default.
+
+p3ZeroConf is enabled by default.
+p3ZeroConfNAT will become the default PortForwarding Service (once tested).
+
+Windows
+----------------
+Under Windows, you require Apple's header files & library to compile.
+If you are missing the libraries, you can disable their compilation in libretroshare.
+
+Furthermore - it'll only work if the Apple DNS Service is running on the Windows PC.
+p3ZeroConf will be enabled by default (if included in the compilation).
+p3ZeroConfNAT will not be enabled by default.
+
+Linux
+----------------
+Neither of these classes will compile or be enabled under Linux.
+There is another library: Avahi - which provides ZeroConf services.
+It is likely to have a totally different interface - 
+so it will have to be coded up separately.
+
+
+