Allow User-added-CAs in Android 7.

[maikbrueggemann]

See:

• https://android-developers.googleblog.com/2016/07/changes-to-trusted-certificate.html
• https://developer.android.com/training/articles/security-config.html

[maikbrueggemann]

Maybe related to #333

[JulienVdG]

I can confirm this works. I've been waiting to get my new computer before trying to fix this. But this pull request fix exactly my issue. Thanks Nils for maintaining this tt-rss client, and thanks maikbrueggemann for beating me at fixing this issue that prevented me to read my feeds on my phone for too long now. Back to reading 200 unread posts :)

[nning]

I can also confirm this works for me.

[micha137]

+1