v0.9.0

0.9.0 (First "Kart" release)

Major changes in this release

• First and foremost, the name — we're now called Kart!

Other changes

• Various local config and structure which was named after sno is now named after kart - for instance, a Kart repo's objects are now hidden inside a .kart folder. Sno repos with the older names will continue to be supported going forward. To modify a repo in place to use the kart based names instead of the sno ones, use kart upgrade-to-kart PATH.
• import & init are often much faster now because they do imports in parallel subprocesses. Use --num-processes to control this behaviour. #408
• status -o json now shows which branch you are on, even if that branch doesn't yet have any commits yet.