Fixed undo area on about:newtab
allow system theme to set menu text color and hover background colors
use system menu text color for active 'menu bar' item
Merge pull request #185 from jackinloadup/system-theme-menu-colors

Use system theme menu colors
Merge branch 'upgrade-to-21'
Bumped up to version 21.1
Merge branch 'master' into upgrade-to-22