- minor changes to some icons (can't see a difference in some of the
cases?), larger changes to others (e.g. mark unread)
- xhdpi assets for a bunch that were missing
Change-Id: Id71d22aa50440cf6c83e4244bb807e3d237949c6
Use the new icons where appropriate. This is not a complete change as there are
still some icons missing.
Change-Id: I51d1458749343ddfc6456dc2a9853b8bc2540e26
