Add version check when loading solution

[vilge]

It's a really usefull feature: I had a strange error message when I tried to load shared solution made in another version. If I have a message "incompatible client version" or something like this i'll have much more information what's happened.

[tamirh]

Yes, the message was cryptic for this latest file version change. We'll make sure in the future to display something more understandable.