Add V2 Changes and Update Roadmap

[cloneofghosts]

I've updated the API specification page to include all of the V2 changes and updated the roadmap. @alexander0042 You'll probably want to look at the roadmap since I'm fairly certain it is not correct and just look over the changes elsewhere to make sure everything is good.

This can be merged once V2 has been launched and will fix #185

[cloneofghosts]

Since V2 is going live today @alexander0042 it would be great if you could review my changes so the docs can get updated with the new changes.

I didn't update the documentation for cloudCover and apparentTemperature but they will need to be updated with the changes in V2. Also I wasn't sure about the roadmap so you'll likely need to review and update as needed. You can make any changes you need in the v2-documentation branch if needed before merging in.

[alexander0042]

Yes, looking at this now! Thank you so much for putting it together

[cloneofghosts]

@alexander0042 Have you had a chance to look at this yet? It's been a few days since 2.0 launched and the docs haven't been updated yet.

[cloneofghosts]

I haven't heard anything on this since the launch of 2.0.1 and I figured it'd be better if the docs get updated even if not 100% correct. You can go in afterwards and make any changes that you need to in order to get the docs 100% correct.