fixes to login page: removed not needed login.sass; removed fixed string length assumption; fixed login button not showing up in Chrome when the form is pre-filled

Various fixes for OS X installer: now installs ree the right way, adds mysql to launchctl, creates & migrates the db, and copies app_config.yml

Something in devise broke for the :mobile format. More investigation needed; we're having this same issue on log out and incorrect password on mobile (though those pages are at least still usable).

There's now a setting in app_config.yml, :enable_splunk_logging, which if true outputs godawful machine-readable splunk logs. It's false in test and development, and true elsewhere.