A couple questions about CodeIgniter 3 (not release date)

[eluser]Unknown[/eluser]
Firstly, are there any plans to integrate a simple authentication library into the base installation of CI 3?

If not, will current libraries designed for CI 2.1.4 be forwards compatible or will they have to be rewritten or at least tweaked?

Also, how difficult will the process of upgrading from 2.1.4 to 3 be?

Finally, more of a subjective question; at this point in time, does it make sense to start new projects with 2.1.4 or 3?