Ianjorgensen/message image tag

This is the icon on notes project i worked on the hackathon, i want to code to be there so when we have icons we can use we can simply add the regex's and it will all just work. cc @jebeck  @nicolashery 
Whatever it takes to be able to view/test this in tideline (with the exception of message creation, of course) is what I'd like :)

And I'm sorry for this, but can you create a new branch with copy-pasted changes? I'm a little worried about the volume of changes in tideline since this was created...