[EuroPython] Please update the register form with new prefixes

[Itamar Shtull-Trauring]

These are quotes from a conversation:

<awoman> python conference ppl didnt have a miss field
<awoman> I think the message is "single girls not welcome here"
<awoman> which certinly exmpains a lot...
<itamar> I'm gonna write the europython list about that
<awoman> please do! and tell them I won't wear my nametag. Nobody will flirt 
with me!

So, please add "Ms." to the signup form now! Obviously having only "Mrs." is 
not good.