Bring tag behavior in line with builtin messages

[nthall]

This PR fixes issue #21 -- it adds a level_tag property to the message model, and adds a custom message manager with a method that automatically adds any applicable level_tag to any user-defined tags. Result is that tag behavior now matches builtin messages. I didn't add any new tests for this functionality; I just changed the existing tag-related assertions to match the new expected behavior. I'm happy to add new tests if you think it's necessary.

[nthall]

Hi, just checking in - if there's something I need to fix to get this accepted, I will happily fix it.

[reinout]

(Helping a colleague with his pull request, so I'm browsing the others)

A quick win would be if you'd pull in master so that you get the tox.ini + .travis.yml for the automatic tests, I guess.

[nthall]

Hi, I have some time and attention for this again. I'm sorry for being dense but I don't know how to change this to get Travis to run. Do I need to close and do something differently in a new pull request? Is there something else I need to fix?

[reinout]

Well, it all depends on the project maintainers to do something. What you could try in your branch:

$ git fetch
$ git merge master
# see if it all works still
$ git push

That ought to put the ".travis.yml" from master into your branch, which ought to automatically configure travis to actually run. So you'd only have to do the merge from master.

(Having the automated test makes it easier to get someone to merge it).

[nthall]

Thank you @reinout ! And now I have passing checks but an ugly commit history - is it safe to rebase this and force push or should I just leave it?

[reinout]

I'm not a hero with git, so rebasing and so always feels dangerous to me (probably unfounded). You'll have to ask one of the maintainers ( @palazzem?), I don't maintain this project, I was just passing through :-)

[nthall]

OK, I've rebased on top of master and cleaned up the commit history. Would love to resolve this at last :)