Various improvements

[rgaudin]

Here's a collection of individual small fixes for identified issues:

• Fixed #29: using default values on Creator init
• Fixed #37: fixed __repr__ for ReadArticle and File, added on Article
• Fixed #38: raising NotFound on unavailable article. this might not be wanted as per discussion on #38 and matthieu's suggestion to leave that to new libzim's. I believe this might be forward compatible but we can strip this out if we think it won't.
• Issue #38: added has_article(url) to test an URL. Currently uses the NotFound exception but could be changed to use RuntimeError should we opt NotFound out.
• Fixed #30: get_metadata() now returns a dict of metadata Didn't receive comment on that issue so I impl. what made sense to me.
• Fixed #45: Creator now accepts pathlib for filename
• 1e65ca5 simplifies the public Creator API by refactoring what's used only once and by using better docstrings and annotations. warning: added a ._closed prop to avoid the double-close issue we'd get on exiting the contextmanager and (auto) deletion.

Please look at them individually and let me know which would make sense to push as separate PRs.

[rgaudin]

@mgautierfr , all your comments have been addressed. There isn't much actual code change beside moving blocks around in the whole PR so I kept it all here.

You can look at individual commits for a quick lookup.

What's changed since last review:

• main_page is now mandatory on Creator
• test on default params for Creator don't inclue dummy assert True
• get_article_by_id() now raises RuntimeError on out-of-bound – actually anything but not art.is_good(), the try block have been removed.
• get_article_by_id()'s id param was renamed article_id to not use reserved keyword
• has_article() method have been removed
• get_metadata() returns bytes of content of a single metadata article and not the discussed dict.
• all references to mandatory metadata are gone
• Creator former methods which had been moved inside close() (as used there and once) have now been put inline, still in that close() method.
• All docstrings were fixed for the reader API
• added __enter__ and __exit__ (does nothing) on reader so it can be used as a context manager (syntax sugar only)

[rgaudin]

OK thanks ; will do soon

[rgaudin]

Sorry about the delay, was a bit of a pain to reconcile but it's now clean and ready.

[mgautierfr]

I'm sorry but it is not totally clean yet :) Commit ed2267b (#47) remove the str in the test, but the acceptance of pathlib as argument come in the commit just after (https://github.com/openzim/python-libzim/pull/47/commits/5ecfab69ffe0586899cbd4ec8a3266c40ea88014)

About the execption, maybe we could return KeyError and IndexError instead of NotFound or RuntimeError. But we could change this in another PR, this one is long enough.

[rgaudin]

Ah! right, don't be sorry for my mistakes. Will do.

[rgaudin]

@mgautierfr That should be good now. Rebased on master. Tests pass on every single commit.

[mgautierfr]

We are good !