BridgeAbstract will return 3600 seconds by default, so the function
can be removed from any bridge implementing getCacheDuration
returning the same value.
Documentation updated accordingly.
It seems that anti-hotlinking method (data-src + JS) was disabled on Rue89 site.
Because I'm not sure that modification is permanent, I put an "if" for testing it before replacement.
--> tested ok on my rssbridge instance. IMG are back.
