Now that we are not directly using message in the message list view
rename the uses of message that are message_containers.
(imported from commit 5c355703a8934a74864f5de6ecb1e2fd851e5d41)
The goal is to have a more data centric piece that can be unit tested.
We also try to minimise the number of one off jQuery DOM updates and
rerender handlebars fragments instead. This will prevent the
message_group and DOM from drifting apart and not being able to rerender
correctly.
(imported from commit 03f09803f2bc0c3b8187f76f2cfe90be9f7512a3)
Previously topics weren't being highlighted at all and messages had their
highlighting persist across different narrows (because we were only checking
whether the message object had a match_content property, not whether it should
currently be used).
(imported from commit 44c91c6d5799dcdf765e19e1a17bd727ce80c918)
Now that we no longer use tables for our message list, we can
more logically group messages together.
(imported from commit 9923a092f91a45fe3ef06f2f00e23e4e3fb62a37)