added unbound to external deps

external/unbound/libunbound/python/doc/examples/example2.rst

@@ -0,0 +1,41 @@
+.. _example_setup_ctx:
+
+==============================
+Lookup from threads
+==============================
+
+This example shows how to use unbound module from a threaded program. 
+In this example, three lookup threads are created which work in background. 
+Each thread resolves different DNS record. 
+
+::
+
+	#!/usr/bin/python
+	from unbound import ub_ctx, RR_TYPE_A, RR_CLASS_IN
+	from threading import Thread
+	
+	ctx = ub_ctx()
+	ctx.resolvconf("/etc/resolv.conf")
+	
+	class LookupThread(Thread):
+		def __init__(self,ctx, name):
+			Thread.__init__(self)
+			self.ctx = ctx
+			self.name = name
+
+		def run(self):
+			print "Thread lookup started:",self.name
+			status, result = self.ctx.resolve(self.name, RR_TYPE_A, RR_CLASS_IN)
+			if status == 0 and result.havedata:
+				print "  Result:",self.name,":", result.data.address_list
+	
+	threads = []
+	for name in ["www.fit.vutbr.cz","www.vutbr.cz","www.google.com"]:
+		thread = LookupThread(ctx, name)
+		thread.start()
+		threads.append(thread)
+	    
+	for thread in threads:
+		thread.join()
+
+