Just returned today from after watching Age of Ultron in the cinema for the third time!
Thor specifically mentions to Tony and cap at the end that if he (Vision) can wield the hammer he can keep the gemstone and so he's worthy. Also Thor said the gemstone is safe with the Vision as being safe (meaning keeping the gemstone safe) is in short supply these days.
Also I made an error in the previous post - Tony doesn't mention the word 'Vibraniumish' when referring to Ultron Prime, rather he specifically said something along the lines of him having a Vibranium Cocktail lol!
One interesting thing I cleared up when some guys said that Ultron could of accessed missile and nuclear warhead codes to make them launch and cause the destruction of Earth, mankind etc, since he could hack through the Internet, well the irony is that he actually could not and was unable to - I'll explain:
I paid attention during the conversation that took place at Hawkeye's house with the team and Fury said that though Ultron's trying to get access to the missile codes there was someone on the other end constantly updating and changing the codes.
So Black Widow goes "We have an ally"?
Then Nick Fury continues with the conversation.
Then I was left thinking who is this ally, but then....
However after on it is confirmed that this other person who's constantly updating and changing the codes was (lo and behold) no other than Jarvis. Tony said that to Bruce during the Vision prep stasis scene. Tony also said and that Jarvis was already been beating Ultron from the inside, and that is also what he was referring to.