[he6390] Add visualization

work in progress
Merge branch 'master' into he6390-add-visualization
[yn9566] Add 'ag attic' to list removed issues
Merge branch 'master' into he6390-add-visualization

Conflicts:
	include/ag.rb
[im2893] Diversify 'ag locate' to show branches, commits, authors and diffs
Merge branch 'he6390-add-visualization'