Add NapiProjekt provider

[bogdal]

This PR adds NapiProjekt provider.

Fixes #384

[Diaoul]

This looks like a very complete PR. I'll review soon, thanks for your work.

[radekbenkel]

@bogdal Thank you for that PR! 🍺 Wanted to do this myself - good that I checked PR section first;)

@Diaoul I see that it's merged to master, but I don't see those changes in latest 1.0.1 release - was this removed after all?

[Diaoul]

It was merged into master by error. I merged it to develop instead.

[castortray]

when we can expect that napiprojekt.py provider will be added to master release ?

[Diaoul]

@bogdal: the provider doesn't seem to work anymore. Unittests are failing: https://travis-ci.org/Diaoul/subliminal/jobs/88170450#L395

[bogdal]

@Diaoul ok, I will check.

[bogdal]

@MichalE7 It looks like napiprojekt gives subtitles in a different format than srt. I assume that we should convert them on the provider level.

[MichalE7]

@bogdal on provider level it means where and who can do it? Sickrage, subliminal or napiprojekt itself?
Here is the screenshot of napiprojekt standalone application settings.

Based on wikipedia :) srt subtitles should look like the ones downloaded from napiprojekt standalone app: https://en.wikipedia.org/wiki/SubRip

[Diaoul]

The format you downloaded with subliminal looks like MicroDVD. Not sure why napiprojekt doesn't return consistent subtitle format, this should be handled by subliminal.

[MichalE7]

I did some more checking.
Default setting for standalone app is to download subtitles in 'Original' format so I suppose it downloads subtitles in the format that was uploaded to the database without any conversion.
In settings you can chose to download subtitles in SRT format which are probably converted from the original. I guess conversion is missing in the script.

Additionally while browsing sites I came across dragon666 project called napi which includes a script to detect and convert subtitles format.
It can be found here: https://github.com/dagon666/napi

[Diaoul]

Subliminal can detect a valid/invalid subtitle file with

subliminal/subliminal/api.py

Line 157 in e0788be

if not subtitle.is_valid():

It should be done when using the CLI, I wonder why it didn't happen here.

I plan to develop a subtitle file format converter for any kind of format with a special focus on TTML for features. For now I think the best is to just discard them somehow and check why the result did get past the is_valid test with proper unittests.