Add conference id to events and favorites

Change-Id: I9bfa2aad533a1de595a4509a3549410205d7d951
Reviewed-by: Caroline Chao <caroline.chao@digia.com>
Update qt developer days logo

Change-Id: Id15c0637e96e0941aeae384b591f3440e7ab3b4b
Reviewed-by: Caroline Chao <caroline.chao@digia.com>