Teach CGit to print an ASCII art commit graph to the left of the commit message, similar to 'git log --graph'. The graph adds extra lines (table rows) to the log when needed to add/remove/shuffle edges in the graph. When 'showmsg' is enabled, the graph is automatically padded to account for the extra lines added by the commit message/notes. This feature is controlled by a new config variable: "enable-commit-graph" (disabled by default), and individual repos can control it by setting "repo.enable-commit-graph". Signed-off-by: Johan Herland <johan@herland.net> Signed-off-by: Lars Hjemli <hjemli@gmail.com>