Add basic test (WIP).

tests/test.py

+from opcua import Client
+
+client = Client("opc.tcp://k2-osie:4840/")
+
+try:
+  client.connect()
+
+  # Client has a few methods to get proxy to UA nodes that should always be in address space such as Root or Objects
+  root = client.get_root_node()
+  children_list = root.get_children()
+
+  var = client.get_node("ns=1;s=i2c0.relay0")
+  i2c0_relay0 = var.get_value()
+  print  i2c0_relay0
+finally:
+  client.disconnect()