Integrate the minunits worker.
Improve test comment.
Merged master.
Merged master.
Checkpoint.
Fix a comment.
Merged master.
Removed Joined from RelationUnitsChange
Changes after review
Merged branch master.
all: remove unnecessary panic("unreachable")
Changes after review
[r=frankban] Integrate the MinUnits worker.
merge trunk;
[r=dimitern] state/watcher: RelationUnitsChange -Joined

Removed the Joined field from RelationsUnitsChange
struct, used by the RelationUnitsWatcher, because
it's not used anywhere and not properly tested.

Added a note about UnitSettings.Settings field
being unreliable as well, and probably needs
removal as well.

https://codereview.appspot.com/12344043/

R=fwereade, rogpeppe
add back some panic(unreachable)s
another one
[r=rogpeppe] all: remove unnecessary panics

With Go1.1, these panics are no longer necessary.
There are only three now left in the tree.

https://codereview.appspot.com/12349043/