New namespace package layout

[spookylukey]

First stab at #79

[spookylukey]

Notes - see:

• https://packaging.python.org/guides/packaging-namespace-packages/#pkgutil-style-namespace-packages
• https://github.com/pypa/sample-namespace-packages/tree/master/pkgutil#practical-usage

[spookylukey]

Hmm, that's weird. I got exactly those failures first time I tried, turned out to be due to git 'fixing' up the whitespace in some of the files, since I have this in my global git config:

[core]
  whitespace=fix,-indent-with-non-tab,trailing-space,cr-at-eol

So, I then overrode that locally:

git config core.whitespace ''

and re did the 'git mv' commands. Now everything works locally, the tests pass. But not on Travis. So it seems that when I pushed, something else applied that same git whitespace config...

[spookylukey]

Hm, it seems that git is still actually rewriting the file when I do 'git mv', but on disk it just moves the existing file, so that what you have in the repo is different from what you have in your working directory. And it doesn't tell you that when you do git status. Nice...

[stasm]

This looks great, thanks so much @spookylukey for working on this! I only have one comment about the name of the distribution as it will be known on PyPI.

[stasm]

I'd prefer to use _ here (or -; practically they're the same), but unfortunately fluent-bundle is already taken on PyPI. I see three paths forward:

1. We go with fluent_syntax and find a different name for fluent_bundle in the same schema, e.g. fluent_runtime.
2. We go with fluent_syntax and re-use the existing fluent package name for fluent_bundle.
3. We use a different separator. According to PEP 426, periods are allowed, too. How about fluent.syntax here and fluent.bundle in Implement fluent.bundle namespace package #81?

Out of the three, I think I like the option no. 3 the most, but I'm open to other opinions.

[spookylukey]

Option 3 also looks good to me. My choice of _ was due to following the guidelines here - https://github.com/pypa/sample-namespace-packages/tree/master/pkgutil#practical-usage - but it sounds like a period could work too. We can try that - I'm concerned the combination with namespace packages might confuse something - and if there is a problem we can think again.