curl input plugin retry mechanism

[pdgendt]

When playing online radio streams, it sometimes occurs that the server resets the request. The current implementation will close the input and stop playback.

It is often a temporary issue that can be solved with re-opening the request immediately. It's a bit annoying now to restart the stream every once in a while because of server issues.

These streams (Danish radio) reset the connections every few hours:
http://live-icy.gslb01.dr.dk:80/A/A05H.mp3
http://live-icy.gslb01.dr.dk:80/A/A07H.mp3
http://live-icy.gslb01.dr.dk:80/A/A29H.mp3

I tried hacking something, but I know it's definitely not how to do it:
master...pdgendt:feature/input-curl-retry