Merge branch 'ml/abandon-old-version' (early part)
* 'ml/abandon-old-version' (early part):
gitk: allow horizontal commit-graph scrolling
gitk: update aqua scrolling for TclTk 8.6 / TIP171
gitk: update x11 scrolling for TclTk 8.6 / TIP 171
gitk: update win32 scrolling for Tk 8.6 / TIP 171
gitk: mousewheel scrolling functions for Tk 8.6
gitk: wheel scrolling multiplier preference
gitk: separate x11 / win32 / aqua Mouse bindings
gitk: remove non-ttk support code
gitk: replace ${NS} with ttk
gitk: always use themed Tk (ttk)
gitk: use $config_variables as list for save/restore
gitk: remove implementations for Tcl/Tk < 8.6
gitk: Make TclTk 8.6 the minimum, allow 8.7
gitk: remove code targeting git <= 1.7.2
gitk: require git >= 2.20
main
commit
0f3d030de5