[TxMt] Xcode integration

[Chris Thomas]

>     testconvert[1041] *** Uncaught exception: <NSUnknownKeyException>
> [<PBXFileReference 0x50bb30> setValue:forUndefinedKey:]: this class is
> not key value coding-compliant for the key comments.

Fixed. It will now report any unknown ivars, but won't fail. Update  
from SVN and give it another shot.

Thanks,
Chris