PNG export feature using the GCViewer GUI

[aolle]

Hi,

I added the the export graph to PNG feature using the GCViewer GUI. It was only available through console, until now.

Thank you.
Àngel Ollé Blázquez

[chewiebug]

Hi Àngel,

Thanks again for your contribution!

If you ask yourself, why the pull request hasn't got the label "merged" and if you check commit history, you'll see, that I didn't just merge your commit. I squashed the three commits into a single one and rebased it on top of "develop", because it is there, that development of GCViewer happens. "Master" is for releases only (I try to use a git workflow as described by nvie).

If you consider a next contribution, you can help me make the merge easier, if you branch away from "develop".

Thank you very much and hope to see more contributions ;-).

Best regards,
Jörg