Add simple json file export, do not crash on bad projects

[zitzlthotietoevry]

This adds a simple json file output and instructions on how you can use it to uninstall packages with package manager.

Since I had some issues with my solutions, I added some try/catch blocks and error reporting. This should make it more stable and shows the "bad" project.

See also #16

[CLAassistant]

All committers have signed the CLA.

[iTiamo]

When I first checked out snitch, I was thinking exactly of this functionality. I figured I'd check out the repo and found exactly what I needed. Built from source and it works for me. Thx!

[twenzel]

This would be awesome!