Copyright-holder and year information is extracted from git log.
git history begins in 2005. So (C) from 1998..2005 is lost. Also some
(C) assignment of commits where the committer didn't use --author.
This reverts commit b3722f7063.
In some cases ardour shows context-menu on right-mouse-button
release. In this case selecting a menu-entry should happen
with the left-mouse button (or any button?!)
Using ev->button is only correct if the menu is temporary and only
visible while the button is held, button release then activates the
menu-item.
This needs further work, in some cases allowing any button (0) to work
makes sense and overall consistency needs to be improved.
Different places use different strategies for context-menus which
don't always match the button used in the event-handler.
This is a hotfix (to make TAV context menus work again with left-click)
