Australis uplift in 29

[Justin Dolske]

Firefox engineering management met today to make a decision on if
Australis should uplift to Aurora on the 29 train, or wait one more
cycle to ride the 30 train. On the balance of the arguments, the
decision was made to uplift.

This means:

* After uplift next week[1], Australis will be on both the Nightly
channel (aka Firefox 30) and the Aurora channel (aka Firefox 29).

* Significant development will continue over the next 6 weeks, as we
burn down current Australis bugs as well as new issues found by the
Aurora audience. These fixes will land on both Nightly and Aurora.

* Upon the following uplift (March 17th), we'll again make an evaluation
on uplifting Australis to Beta or holding it back on Aurora for the
Firefox 30 train. There is significant risk to backing out a large
project from Beta, so the intent will be to ride a Beta to Release.

* We will, per previous plans, cease maintaining the backout-branch for
Nightly ("Holly"), and will instead be maintaining a backout-branch for
Aurora. We may (pending further discussion) drop this branch as well
if/when it becomes obvious that we will be uplifting to Beta.

[1] - https://wiki.mozilla.org/RapidRelease/Calendar

Justin