Re-add call statistics.

Author: Danny Baumann <dannybaumann@web.de>
Date:   Mon Nov 11 15:36:21 2019 +0100

    Fix crash in call stats.

    We fed color resources into LinearColorBar now.

    Change-Id: Ica6870fb6af8b982bc2710e7b63092c513fa4755

Author: Danny Baumann <dannybaumann@web.de>
Date:   Mon Dec 2 09:34:22 2019 +0100

    Beautify call stats details category headers.

    Make them consistent with how pref category headers are displayed.

    Change-Id: I4ee8bb2dae11970051552d14df2d58d7ab6a3fdf

Change-Id: I9f2b6e912ca69a5aa7a1790bed06304ee953e752