Seems like I got it working. No idea what made it work, but I think it could have something to do with the wrong library... I used this at first: https://bitbucket.org/fmalpartida/new-liquidcrystal/downloads/LiquidCrystal_V1.2.1.zip
and it produced a lot of rubbish. Not solid blocks, but something that looked like sprites of some kind. But no text as the sketch indicates.
Then I read up on the descriptor thing, and replaced something in the sketch code for the HelloWorld_I2C :
I replaced this:
LiquidCrystal_I2C lcd(0x27, 2, 1, 0, 4, 5, 6, 7, 3, POSITIVE);
and it worked fine. But then I went back to just using this
and it still worked...
What I also did before this, was to download the library again and install it... So not really sure what made it work
But it works, now over to the next couple of steps for my many projects
Thanks for all the good help
Update: I played around a bit more, and I have to use this:
LiquidCrystal_I2C lcd(lcdAddr, 2, 1, 0, 4, 5, 6, 7, 3, POSITIVE);
to make it work.
I guess some code was still residing in the arduino, since I got this when trying to upload the new sketch:
avrdude: stk500_getsync(): not in sync: resp=0x00