added recursive parameter

chose parent reference only if id matches

* fix encoding of LocalizedText and export/import ByteString encoded as based64

* update generated address space

* fix generate address space

* regenerate address space

* add new extensions objects to ua modules to automate decoding

* more work

* first version able to generate binary

* make switch in structures work

* remove binary specific initializer argument

* first version of from_binary that seems to work with DataValue objects

* start change client code to use new binary functions

* logging into prosys server works

* binary functions pass first tests

* client_to_prosys.py seems to work

* server and client work and most tests pass

* remove UInt8 and Int8, merge (mostly) pack_uatype and to_binary

* remove more to/from_binary calls and implementattions

* update custom structure code to new binary generation

* remove dead test, make unit tests pass

* fix bug in header encoding and update xml code to ua_types changes

* refactor some of the crypto stuff and fix circular dependency

* python2 fix

* reverse args of to_binary to be more like from_binary and pack

* fix nodeid support for nsu in binary and string format

* remove dead code and duplications in binary methods

* better error handling in some corner cases

According to OPC Unified Architecture Specification (Part 4: Services,
7.28 RequestHeader) a TimeoutHint value of 0 shall be treated as no timeout:
"The value of 0 indicates no timeout.".

This fixes issues with OPC UA clients never receiving any PublishResponse
if a TimeoutHint of 0 was used in the according PublishRequest.

This is necessary since xml does not contain typeid

* Updated instanciate.py to handle DataType Nodes

Hi, 
I had a bug creating an instance of a Type I imported via XML. Some Nodes where of NodeClass DataType which would trigger the warning l70 then crash l 93 because the object returned was None. 
I hope that my fix is ok with the specification. 
Thx

* Update instantiate.py

updated commit to fit requirements

don't forget to unsubscribe handle for tag1

create_subscription argument period is in milliseconds

* Let the use call a method using a QualifiedName object.

* Correct previous bad commit.