SQLitePlugin: Log query and database name on SQL errors
MPTVSeries: Don't return shows without episodes
MPTVSeries: Correctly count episodes in season, and hide those without any

This fixes some counting inconsistencies, and fixes the season retrieval to do
the same as the show retrieval has been fixed to do in the previous commit.
Also closes #391, by not returning any seasons without episodes.
MPTVSeries: Use id from the database as id for fanart
MPTVSeries: Correctly handle multiple episodes in a single file

Don't skip the second one in the file. This is a very ugly design from
MP-TVSeries. Every time you put a number in the name of a database
column (or an API method... I'm looking at you, Microsoft), something
is going horribly wrong.
WebMP: Catch errors when proxying HLS index

This prevents a domino-offect which floods the logs with four exceptions
instead of only the "regular" "remote-host-closed-the-connection" exception.
Merge branch 'release-0.5-dev' into release-0.5
Library: Correctly handle IPv6 addresses in subnet-testing (closes #394)