Fix for issue #511 to allow AlternatingRowBackground to be set from a DataGrid style
Fixes #540
Fixes #539
MetroTabItem uses ItemFromContainer.
Don't try to remove the TabItem from Items if the TabItem's CloseTabCommand is bound.
Fix for a rare dispatcher exception.
Removed comments and added braces.
fixes #547, simplifies close behaviour to run command handler before closing item
updated demo for MetroTabItem usages