Provide a way to set rounded corners on the outer buttons and to the complete segment control

Currently, there is no ItemTemplate for the SegmentedControl, therefore we need to use an IEnumerable<string>.

Please add support for ItemTemplate, or DisplayMemeberBinding property, so that we can bind to an IEnumerable<T>.

I want to enlarge the font size in the option, but there is no fontsize attribute in this control.

Currently users can navigate through segments with Tab key on Windows - provide a way to go forward/backward through arrow keys as well.