I will try to figure out how github works (I was used to cvs in the past!) and am a bit out of date w.r.t. modern source control!
I will send a patch for my changes to isRunning, and adjust().
I think "isRunning" doesn't exists anymore in the lib, to tell you the truth I was using an older version with isRunning already in place but when I forked I noticed that it has been dropped meanwhile.
We could add it back and ask for a merge (pull request in git jargon), it was definitely a useful function to initalize the clock with compile time when loading the sketch.
Another recent addition to RTClib is an intial support for PCF8563, I've also patched a working lib in the past, it's here: https://github.com/elpaso/Rtc_Pcf8563
, it would be nice to merge the two...