Saving for previous version in VBAI

[sevincom]

In Labview, we have an option for saving the VI for a previous version. I think it would be good if we have this feature in VBAI, too. 

[varga.sm]

I line with this, it would be very helpful for VBAI to warn us before we accidently open a .vbai file in a later version.

 Imagine someone sends me their VBAI code written in 2013 for review.   I open it in 2014, make a small edit like add a comment and send it back.   Now they can't open it and there's no way to get it back to 2013 without re-writing the whole thing from scratch again.   ya ya they should be using source control but too many people still don't.

Steve