Unify/simplify the behavior of per-locale and non-per-locale files by moving per-locale generation to Segment class

[johnnyshields]

This PR unifies/simplifies the behavior of per-locale and non-per-locale files.

Specifically, splitting files per-locale generation is done in the Segment class .save! method, which is the final step before writing the file. (Previously, "per-locale" and "non-per-locale" files followed very different logic paths which diverged early in the processing chain.)

One positive effect of this change is that the "fallbacks" feature now works for both per-locale and non-per-locale files.

Important: There are two breaking changes in this PR, hence I recommend a minor version bump.

1. Per-locale files should now have only/exclude scopes which begin with '*', which is the same as non-per-locale files.
2. Since this PR fixes the issue that fallbacks were ignored for non-per-locale files, users may see some behavior change. for this. This is unavoidable as it's essentially a bug that this wasn't done before.

Lastly, please note that I had to add fallbacks: false to many of the test fixtures to ensure behavior consistency.

[PikachuEXE]

Commented code o_0

[johnnyshields]

All comments have been addressed.

[PikachuEXE]

For your breaking changes:

• For (2), it's fine, it was a bug
• For (1), It's not clear to me for what you are talking about.
  Please clarify it (or write README and add CHANGELOG entry directly :P

[johnnyshields]

To explain (1):

Old format. Note that the %{locale} one doesn't begin with '*'

- file: '/my_dir/not_per_locale.js'
  only:
    - '*.foo.*'
    - '*.bar.*'

- file: '/my_dir/my_%{locale}.js'
  only:
    - 'foo.*'
    - 'bar.*'

New format:

- file: '/my_dir/not_per_locale.js'   # same
  only:
    - '*.foo.*'
    - '*.bar.*'

- file: '/my_dir/my_%{locale}.js'   # now has *
  only:
    - '*.foo.*'
    - '*.bar.*'

[PikachuEXE]

OK, I think that's more consistent and sensible.
Please update README and CHANGELOG so I can merge this.
Thanks :D

[johnnyshields]

Updated README and CHANGELOG

[PikachuEXE]

Common mistake: you have added the changelog entry for a released version o_0

[johnnyshields]

Fixed

[michieldewit]

For the except option the *.something.* format is not supported as is for the only option. It only supports key names. So when errors is specified for the except option, all of the following segments will be excluded: errors, app.errors, app.view.errors. It seems to have always been like this. Please adjust comments in CHANGELOG/README or change the functionality (the latter I would prefer).

[PikachuEXE]

@michieldewit Please open another issue :)

[michieldewit]

I created a pull request for this: #325

[PikachuEXE]

Will review it next week <3