* Add generic r2 graph.
* Add Callgraph widgets
* Add more graphviz layouts.
* Fix some edge cases in graphGridLayout that were more likely to appear in callgraphs
* Refactor the code moving some of the logic out of disassemblyGraphWidget making it more reusable
* Create adapter for converting vertical layout into horizontal
* Fix edge spacing override for edges going out of switch statement.
* Update documentation.
* Rewrite node placement and edge routing parts of graph layout code
* Document the high level structure of layout algorithm
* Tighter layout and less edge crossings
* Better worst case memory and CPU usage
* Limit how far outside image view can be moved
* Allow using main view as overview by zooming out
* Fix showBlock position calculation when zoomed out
* Rewrite block sorting and placment so that unreachable blocks are processed.
* Use DFS instead of Kahn's algorithm for toposort as it makes it easier
to deal with loops.
* Remove unused code
* Separate graph layout code from GraphView.
* Remove formatting and grid layout specific code from GraphLayout.
* Copy edge styles from from main graph view to overview.
