Fix DidDefaultSettingsChange to detect changes when a Command was moved from one HotkeySettings to another
Move "Go to current revision" and "Go to commit..." from FormBrowse to RevisionGrid MenuCommands

- to make them also available in the RevisionGrid context menu
- also move Hotkey definition from FormBrowse category to RevisonGrid
Make GotoCommit shortcut configurable
FormChooseCommit: remove code duplication by reusing revisionGrid.MenuCommands.GotoCommitExcecute()
Fix: hotkey display string was not shown when RevisionGrid is part of another user control (like FormChooseCommit)
update UnitTests