Implement custom AnnotationSchema subclass for NamedTuple

[gwax]

I started building out something very similar with a focus on supporting typing.NamedTuple as a central model construct. After stumbling on your project, it seemed easier to port my work to live on top of marshmallow-annotations than to try and roll my own parallel project.

[justanr]

👍 I'll have to take a closer look when I'm home from work but first glance looks good. Caught a few documentation errors too, appreciate that.

[justanr]

Being curious, how easy was this to implement? Is there anything that the library should do differently in your opinion?

[gwax]

This was pretty easy to implement because it mostly layered on top of what you had already done.

The converter portion took a little thinking but was totally reasonable.

Looking at #11, I think it will be pretty easy to abstract a few pieces of this code and add support for the Python 3.6 dataclasses backport. In anticipation of that, I might rearrange this and move marshmallow_annotations.namedtuple to marshmallow_annotations.ext.namedtuple.

[gwax]

I have moved the core default handling functionality into BaseConverter, put default value stripping behind a Meta option flag, and moved the namedtuple code to marshmallow_annotations.ext.

I think this is good to go now.

[coveralls]

Pull Request Test Coverage Report for Build 69

• 34 of 34 (100.0%) changed or added relevant lines in 2 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 100.0%

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Totals
Change from base Build 64:	0.0%
Covered Lines:	217
Relevant Lines:	217

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💛 - Coveralls

[gwax]

I believe that I have addressed your feedback.

[justanr]

:+1:

[justanr]

:beers: Just released 2.1.0 with this. Figured you wanted to use it in something so might as well make it easy to use.