Remove references to code that's been removed

[strugee]

See MycroftAI/mycroft-skills@da6066e#diff-bbacc29aecae5c3e37042cf23b14652e

[strugee]

Actually, looks like this whole document might need to be reworked. The section about converting to use decorators is outdated too, since as of that commit the template already uses decorators.

[forslund]

You're quite right. The entire document needs to be updated. If you like to tackle that as well we can hold off on merging this. Otherwise I think this can be merged when the CLA lands and we can continue the work in separate PR's.

[strugee]

Honestly I'm just working through the introductory materials myself so I'm not sure how much I'll really be able to explain :P

Why don't you go ahead and merge this when I'm done with the CLA process and I'll file a followup issue to clean the rest up? Then if/when I feel like I've got enough experience I can go ahead and do it myself, or if someone gets to it before me they can take it and run with it too.