update to include METs in the intraday value

I may have jumped the shark with this commit, as we use IntradayData as
the return type for all the minute level stuff but we keep adding more
values that are specific to individual calls. To be re-evaluated, but a
breaking change is inevitable.
Merge pull request #5 from aarondcoleman/master

update to include METs in the intraday value
sln issue again
Merge branch 'master' of https://github.com/WestDiscGolf/Fitbit.NET
merge from master