Merge lp://staging/~charlesk/indicator-power/lp-1388235-use-new-battery-icons into lp://staging/indicator-power/15.04

Use the new power level icons for a more accurate display of the battery level.

== Change Description

The new power level icons added in lp:~tiheum/ubuntu-themes/white-indicators let us show better power level accuracy, so round to the closest 10% instead of closest 20%.

As a special case, since 20% shows 'critical' red, for 21-29% let's round up to the 30% icon so that we don't show critical red when we're at 25%.

Power level can be tested manually with a mock battery; see https://wiki.ubuntu.com/Process/Merges/TestPlan/indicator-power "Notes on Battery Testing"

== Checklist

> Are there any related MPs required for this MP to build/function as expected? Please list.

Works best with lp:~tiheum/ubuntu-themes/white-indicators, but uses the existing icon names as fallbacks so it should "fail gracefully" back to the old icons when not on mobile

> Is your branch in sync with latest trunk? (e.g. bzr pull lp:trunk -> no changes)

Yes

> Did the code build without warnings?

Yes

> Did the tests run successfully?

Yes

> Did you perform an exploratory manual test run of your code change and any related functionality?

Yes.

> If you changed the packaging (debian), did you subscribe the ubuntu-unity team to this MP?

N/A

> Did your component test plan pass? If on a device, what image number?

1. 14.10 krillin r191
2. 15.03 nexus 4 r63

> Please list which manual tests are germane for the reviewer in this MR.

indicator-power/low-power-icon

> Did you provide a link to this page https://wiki.ubuntu.com/Process/Merges/Checklists/indicator-power

Yes