The one actual change was this: To give a KeyError when stuff can't be found in a dictionary, rather than returning None there and then getting a TypeError later.
Contributes to issue CURA-5936.
This was required since Cura 2.1 produced files with the same filename (bar extension). This then resulted in two containers with the same ID. If you had bad luck, an instance container was chosen as global container (depending on which was first in the unordered dictionary). This gives the current settings the postfix _current_settings, fixing that issue.
Contributes to issue CURA-844.
This solution is a bit neater in code. It makes the function perform a single purpose, since it no longer translates a list of setting names but just one. Also it now neatly puts the translations in a separate, easy-to-modify dict. Only disadvantage is when simple key look-up is not sufficient, such as when renaming lots of settings at once, where substring matching would make the code a bit shorter. But we shouldn't do such a rename anyway.
Contributes to issue CURA-844.
Machine instances have the exact same file structure as preferences, except that machine instances require a name field (was already correctly implemented), but preferences didn't require it. This now forbids preferences to have a name field, so that the distinction between the two can be made.
Contributes to issue CURA-844.
This plug-in does nothing at the moment. It merely says that it is able to upgrade configuration from version 2.1 to 2.2, but then raises exceptions when you actually try to use it. This is by design. I will now implement the functions that do the conversion.
Contributes to issue CURA-844.
