MoreCast: Refactor weather parameter tab state into an array

[dgboss]

We're running into a race condition when toggling the visibility of weather parameter tabs and the Forecast Summary tab. To reproduce:

1. Launch MoreCast and click the RH tab so both temp and rh are visible.
2. Click the Forecast Summary tab
3. Click the RH tab.

Actual Result: Temp and RH are both visible
Expected Result: Only the RH tab should be visible.

I believe this is happening due to each tab having independent state for managing its visibility and that we can workaround the problem by using a single object to manage the state of all the tabs.