BREAKING CHANGES:
`$bar-button-wp-color` was renamed to `$toolbar-wp-button-color`
`$bar-button-wp-border-radius` was renamed to
`$toolbar-wp-button-border-radius`
Added `$toolbar-wp-title-text-color` for better control of the title
color
Removed `$toolbar-wp-button-color` from the default themes
references #6364
BREAKING CHANGE:
`$item-ios-divider-bg` is now `$item-ios-divider-background`
`$item-ios-sliding-content-bg` is now
`$item-ios-sliding-content-background`
`$item-md-divider-bg` is now `$item-md-divider-background`
`$item-md-sliding-content-bg` is now
`$item-md-sliding-content-background`
`$item-wp-divider-bg` is now `$item-wp-divider-background`
`$item-wp-sliding-content-bg` is now
`$item-wp-sliding-content-background`
references #5651
