Code review comment for lp:~midori/midori/tabby

I made some improvements to error handling at startup and fixed it to work out of the build folder with cmake. I also resolved the "error" after first startup due to re-creating the tables.

Personally I learn towards merging now. I would look into re-factoring the database creation/ update/ import in a separate branch - I think we don't want to rush it, and it doesn't block tabby.

But I'd like a decision from Paweł before top-approving this. He expressed a strong wish to have the about: page on startup to restore other sessions asap.