Add/erase

[danielpaulus]

A bigger update with the following changes:

• fix bug in dproxy that caused it to fail because of a missing unix:https:// prefix
• fix bug in dproxy that caused it to break analyzing apple configurator

New features:

• the ios lang command now prints a list of all supported languages and locales
• new code to set time and timezone (not accessible through CLI for now)
• ios erase lets you erase the device settings and contents, like Apple Configurator
• ios activate allows device activation non iCloud registered devices. Create a feature request if you need iCloud as well.
• ios prepare enables device preparation and supervision
• ios prepare create-cert adds a convenience method to generate supervision certificates
• ios prepare printskip prints a list of all setup steps you can skip