Support for multiple KNX Interfaces.

[encbladexp]

This pull request enables support for multiple KNX interfaces per smarthome instance. The existing behavior is not changed.

Missing things:

• Documentation
• Item Inheritance (use same KNX Interface on a tree of KNX items)

[ohinckel]

I have implemented a similar feature to support registration of plugins (not only the KNX plugin) multiple times in the plugin confiugration. My implementation consists of two new features:

• Pull request Add plugin methods to smarthome #81 - this add support for plugins to get an unique identifier for the current plugin instance (e.g. useful when registration the scheduler task)
• Pull request Make it possible to attach items to a given plugin #83 - this add support to register a given plugin instance to configured items

To summarize this you can configure the plugins (in plugin.conf) and the items (in items.conf) using the following:

[knx1]
  class_name = KNX
  class_path = plugins.knx
  host = 192.168.X.Y
  ...
[knx2]
  class_name = KNX
  class_path = plugins.knx
  host = 192.168.X.Z
  ...

  [knx1]
    [[item1]]
      plugin = knx1
      ...
  [knx2]
    [[item1]]
      plugin = knx2
      ...

Both is currently not merged, since it touch also the core of SmartHome.py. Maybe this pull request shows that other plugins also need support to be registered multiple times and a more generic implementation would help plugin developers a lot to support this (see pull request #81, which is using this already for the SML plugin).

[encbladexp]

I will port my changes if your pull request gets merged.

[encbladexp]

Rebased on current develop...

[encbladexp]

Rebased another Time. Is there any chance of getting this PR applied?

[cstrassburg]

added to https://github.com/smarthomeNG/smarthome

[ohinckel]

@cstrassburg I just created a new PR smarthomeNG/smarthome#50 which means, that this PR can be changed in that way that is will use the plugin methods introduced by the smarthomeNG/smarthome#50.

Do you merged the stuff to smarthomeNG already?