Yahoo Protocol 15 branch

[Sean Egan]

On 7/27/07, Sean Egan <seanegan at gmail.com> wrote:
> The only change between this and current trunk is that the Yahoo!
> protocol version number has been bumped from 0x0c to 0x0f. I've
> created a new milestone for merging this branch; I've set the deadline
> to the same date as the MSNP14 branch.

Realizing that the only three ChangeLog items for 2.1.1 so far are
Yahoo-related, I decided to change the Yahoo protocol version in trunk
to 15 instead, and if it's not ready in time for 2.1.1, we can revert
it then.

I understand buddy-list management was the biggest identified issue
from this last time we tried. Please help test and fix.

-s.