[MERGE] Make knits the default format

[Johan Rydberg]

Robert Collins <robertc at robertcollins.net> writes:

> +    * 'knit' is now the default disk format. This improves disk performance and
> +      utilization, increases incremental pull performance, robustness with SFTP
> +      and allows checkouts over SFTP to perform acceptable. 
> +      (Robert Collins, Aaron Bentley).

It feels odd to ask, but could I please get some recognition?  

~j