Fixes/264 scrolling up should reset search state

[reekypete]

Basically implemented a "reset-in-code" model for app state.

I've attached this mostly to the search buttons (since scrolling up isn't reliable enough to reset state)

I.e. when a user click search, reset state before doing anything.

The only exception is app.level, which gets set by the "Primary" & "Secondary" buttons. I reset this when a school is searched by name

[techieshark]

See comment on #264. If this is still an issue, please reopen that and also use git rebase -i master on this branch to remove unrelated commit (fixes/262...) and squash very related commits 925b3ae and 5fbeefc into one (see this comment for details on git rebase).

Thanks!

[techieshark]

Incorporated into #297, thanks!