Add socket examples (simple HTTP client and server).

examples/unix/sock-client.py

+mod = rawsocket
+s = mod.socket()
+
+if 1:
+    ai = mod.getaddrinfo("google.com", 80)
+    print("Address infos:", ai)
+    addr = ai[0][4]
+else:
+    # Deprecated way to construct connection address
+    addr = mod.sockaddr_in()
+    addr.sin_family = 2
+    #addr.sin_addr = (0x0100 << 16) + 0x007f
+    #addr.sin_addr = (0x7f00 << 16) + 0x0001
+    #addr.sin_addr = mod.inet_aton("127.0.0.1")
+    addr.sin_addr = mod.gethostbyname("google.com")
+    addr.sin_port = mod.htons(80)
+
+print("Connect address:", addr)
+s.connect(addr)
+
+s.write("GET / HTTP/1.0\n\n")
+print(s.readall())

examples/unix/sock-server.py

+mod = rawsocket
+s = mod.socket()
+
+ai = mod.getaddrinfo("127.0.0.1", 8080)
+print("Bind address info:", ai)
+addr = ai[0][4]
+
+s.bind(addr)
+s.listen(5)
+print("Listening, connect your browser to http://127.0.0.1:8080/")
+
+counter = 0
+while True:
+    res = s.accept()
+    client_s = res[0]
+    client_addr = res[1]
+    print("Client address:", client_addr)
+    print("Client socket:", client_s)
+    print("Request:")
+    print(client_s.read(4096))
+    #print(client_s.readall())
+    client_s.write("""\
+HTTP/1.0 200 OK
+
+Hello #{} from MicroPython!
+""".format(counter))
+    client_s.close()
+    counter += 1