adding and testing Indigo 5 support

[MartySkinner]

To use the XML RESTful API on an Indigo 5 system or for testing on any Indigo 6 system, add this line to ~/.homebridge/config.json in the middle of the "platforms" section:

"version": "5",

The version of xml2json I used as a dependency is https://github.com/buglabs/node-xml2json#readme, and also can be installed via

npm install [-g] xml2json

/Marty

[webdeck]

Hi Marty. Thank you for submitting this pull request. Sorry for the delay in my response - work has been very busy.

Could you please make the following changes:

• Update the comment at the top of index.js to document the new version configuration item.
• Update README.md and sampleconfig.json to show the new configuration item (show value as "6" here as the default)
• Move lines 307-330 into a helper function to make it cleaner
• For lines 157-166, this would be cleaner if you defined a variable for the proper extension ("json" or "xml") based on the version config, and then you wouldn't have redundant code to set requestURLs.

Thanks,
-Mike