Invert inhibitAdvancedLogin default, implement alternate server cleanup.

To test this, you have to have your server set to something other than
spideroak.com, which requires inhibitAdvancedLogin to be false.  Then,
allow inhibitAdvancedLogin to be true, and restart the app.  You should
be prompted, and can try refusing and than, on another restart,
accepting the change.
Merge branch 'master' into issues-466-469-invert-advanced-login

Bring up-to-date.
Merge branch 'master' of https://github.com/SpiderOak/SpiderOakMobileClient into issues-466-469-invert-advanced-login
Merge branch 'issues-466-469-invert-advanced-login' of https://github.com/SpiderOak/SpiderOakMobileClient into issues-466-469-invert-advanced-login
Slightly friendlier button text
Changed wording a bit
Merge pull request #475 from SpiderOak/issues-466-469-invert-advanced-login

Invert inhibitAdvancedLogin default, implement alternate server cleanup.