Add sha1 to the DiffWidget
GraphView in White, more explicit colors
Comment OpenGL stuff. Is it really useful ?
Do not draw sha1 as text
Draw a circle for commits
Different values for drawing the graph
Major Edge rework... Looks quite good IMHO :)

Need to fix some white spaces that still appear between elements.
Better GraphView display, by playing on radius, offsets, and colors
Fix bug due to refactor height as commit_radius
Remove Cruft
Remove Cruft
Use QPainterPath for drawing edges : cleaner, faster, sexier !
Unique y position for commits

But now, x positions seem a little off in complex branch schemes...
Don't think we need reduce here, simple max or min should be enough
Revert to not using node.is_merge()
Start reworking labels
Some more tuning on the labels
Show 10 commits on startup
Use a ComboBox for selecting branch to visualize
Fix Combo Branch not being filled correctly when git-dag launched from git-cola