Some old stuff remained after the upgrade to per-user passcodes

Cleared out remaining refs to settings.getOrDefault("passcode") or settings.getOrDefault("passcodeTimeout")

Replaced with accountModel.getPasscode() and accountModel.getPasscodeTimeout()
Complete @devgeeks switch to just using the AccountModel's notion of the
current passcode and passcodeTimeout, rather than having the
AccountModel manipulate the app-wide settings.

As I expected, there were a lot more changes to make to switch over to
using just the account model for passcode values, rather than having the
account model manipulate the app-wide passcode as I originally did.
However, it does yield a simpler overall scheme, so it ultimately is the
right thing to do.
Merge pull request #413 from SpiderOak/issue-412-passcode-timeout-regression

Issue 412 - passcode timeout regression