Allow for multiple call icons in the call log.

This commit adds support for having multiple call icons on a single
entry, to handle group entries.

When the group is represented as text, we currently use only the first
call type, but, in a follow-up, I will use an additional counter.

Change-Id: Iaa9d1c84eb926c1500bf0a439d45ce59314bd198
7 files changed