MCO-489 Avoid clashing with puppets monkeypatch

When loading the puppet agent we load puppet library into the ruby intepreter,
which comes with it's own set of monkeypatches one of which redefines the
initialize of OpenSSL::SSL::SSLContext using the same private method,
__original_initialize.

This causes deep recursion if MCollective needs to reestablish the connection
to the middleware after loading the puppet agent:

    error 2014/10/21 10:16:09: rabbitmq.rb:45:in `on_ssl_connectfail' SSL session creation with stomp+ssl://mcollective@127.0.0.1:61614 failed: stack level too deep

With this patch we change the name of the private method created by our
monkeypatch to __mcollective_original_initialize which avoids the clash/recursion.
Merge pull request #254 from richardc/MCO-489-duelling_monkeys

MCO-489 Avoid clashing with puppets monkeypatch
MCO-484 restructure 'Writing SimpleRPC Agents' for 2.6.0

With this commit we rewrite the demonstration agent so it works directly
against MCollective 2.6.

We also remove the references to older version 2.x behaviour, and
restructure the document in an attempt to tour the moving parts of agents and
actions more naturally.

New Structure:
* Conventions regarding Incoming Data
** Sample Agent
*** Agent Naming
** The DDL
** Actions
*** Declaring in the DDL
*** Implementing in Ruby
**** Accessing Input
**** Running Shell Commands
*** Implementing with external_action
** Constructing Replies
*** Reply Data
*** Reply Status
** Sharing code between agents
** Authorization
** Auditing
** Logging
** Data Caching
** Processing Hooks
** Agent Configuration
** Agent Activation
Merge pull request #249 from richardc/MCO-484-agent_tutorial_meets_2.6

MCO-484 restructure 'Writing SimpleRPC Agents' for 2.6.0
MCO-456 expose target collective to discovery plugins

With this commit we expose the target collective to the discovery plugins, by
adding a key "collective" into the filter hash.

It's expected to be useful in the mongodb discovery filter per this
mailing list thread:
https://groups.google.com/forum/#!msg/mcollective-users/wMk2ms5yp5M/11OEJT6MxewJ