Persist some information between refreshes

[Tathanen]

It's always been a bit of a pain that when the wall is reloaded, it reverts to only knowing about the first API hit. Certain data should be stored in localstorage, things like build totals, developer profiles, maybe the master repo list (and then add an expiration time for untouched repos so we don't have ancient stuff in there). Also respect the start-of-the-week limit so on refresh, the "weekly totals" don't include data from the previous week.

Include a "clear cached wall data" command in the advanced settings.

[Tathanen]

While you're at it, put another "clear data" button on there to revert the wall to factory built settings, and remove the contents of localstorage entirely.