Bump last known versions.

[neonichu]

Xcode 6.3 brings a new project format:

While at it, I also bumped other "last known" constants.

Why is this WIP? Bumping LAST_KNOWN_OBJECT_VERSION would mean that older Xcode's wouldn't be compatible anymore - I guess we should have two constants now? Using the older one for generating project files, but not erroring for 6.3 ones?

[neonichu]

BTW, haven't found what is actually different in the "new" format, seems to be identical for some project files I tested, except for the versioning constant.

[kylef]

Let's hold off with this until 6.3 GM is out.

[kylef]

Also, perhaps we can introspect the user's project to determine which version to use.

[neonichu]

So 6.3 is out now. Introspection is already happening if an existing project is opened. The open question is: what to do if there isn't?

1. Default to latest version, 6.3, this is how we have been doing it.
2. Default to the 3.2 format.

Additionally, we could allow to pass in an object version to the Project initializer - that would allow CP to generate the Pods project with the same version as the user project.

[AliSoftware]

Same as user project seems the most logical choice IMHO.

[neonichu]

This is now ready to be merged.

Using the old 3.2 format is the default for completely new projects, when opening projects the current format is retained. There is also a new parameter to the initializer which will enable CP to infer the format from the user project.

[neonichu]

@mrackwitz @kylef what do you think?

[segiddins]

👍 @neonichu please bring home this integration in CocoaPods?

[jakepetroules]

Did you guys ever find out what actually changed in the 6.3 format?

[neonichu]

Nope, did you find anything?

[yar1vn]

Any updates on the Xcode project format? Had the same issue this week and went back to 3.2 but took my a while to figure it out. Thought the podfile was broken at first.

[pichirichi]

Same happen now with Xcode 8.0, when changed back to Xcode 6.3 all is fine.