i18n for all strings

[janm399]

The server should not store any text to be displayed to the users. Anything to be displayed to the user needs to use some i8n key. See https://github.com/eigengo/lift/blob/master/ios/Lift/Base.lproj/Localizable.strings. For example, exercises should be

"exercise.arms"="Arms";
"exercise.arms.bicepcurl"="Bicep curl";

And so on. We need to hunt down all non-it8n strings and move them to the localizable properties.