Convert !TabContainer (specifically the tab buttons and the left/right scroll buttons) to use _CssStateMixin.   Also fixed some CSS names that didn't contain "dijit":
Convert !TabContainer (specifically the tab buttons and the left/right scroll buttons) to use _CssStateMixin.   Also fixed some CSS names that didn't contain "dijit":

{{{
.dijitTab .closeButton --> .dijitTabCloseButton
.dijitTab .closeButton-hover --> .dijitTabCloseButtonHover   (close button for individual tab)
.dijitTabBtnDisabled --> .dijitTabDisabled   (left and right scroll buttons on tab strip)
.dijitTab .closeImage --> .dijitTabCloseIcon   (icon inside of close button)
.dijitTab .closeText --> .dijitTabCloseText      (text inside of close button, for a11y)
}}}

Refs #10613 !strict.

git-svn-id: 674a2d6b1e32e53f607eb824547723f32280967e@21144 560b804f-0ae3-0310-86f3-f6aa0a117693

kitsonk/delite,kitsonk/delite,harbalk/delite,harbalk/delite,Sam-Cummins/delite,Sam-Cummins/delite