Use a common save dialog for exporting call graphs
This lets you pick where the saved call graph visualization should go, and what format you wanted it in. Previously, it generated a dot file, and on Unix, a PostScript file. This lets you choose a dot or PDF file (instead of PostScript, which is less common these days), rendering to an intermediate dot file if needed.
This also changes the context menu in the per-function graph too, increasing commonality in code.
More formats can be added as needed; PostScript would be trivial to restore, as would any other GraphViz supported formats.
Possible caveats:
- QProcess might be blocking.
- Maybe people really do want PostScript... it's trivial to re-add.
Edited by Calvin Buckley