911630 "Update "flyout" typed MenuCommand"
911686 "Cascading Flyouts & Menus"
     Some of the work that was done for 911630  includes:
     -Redline CSS updates.
     -"flyout " typed MenuCcommands display a chevron to indicate that they invoke a sub flyout/menu
     - mouse hovering over a "flyout" typed MenuCommand for 400ms will inoke the associated sub Flyout/Menu.
     - unit tests

     The work for 911686  contains:
     - A new private singleton class in Flyout.js, "CascadeManager" is used to manage the lifespan of multiple open menus/flyouts at once.
     - Left arrow key will close the current subFlyout/subMenu and take you the parent menu. If there is only one Flyout/Menu showing, then left arrow key does nothing.
     - If a menu contains a "flyout" typed MenuCommand, the sub menu assoicated with that command can be invoked with the right arrow key when that command is focused.
     - Pressing either "Alt" or "F10" inside of a flyout/menu will close all open Flyouts/Menus.
     - Showing a flyout/menu whose anchor HTMLElement is inside of a currently shown flyout/menu, will append the showing flyout to the cascade as a child of the  flyout that contains the anchor element.
     - Showing a flyout/menu whose anchor HTMLElement is not inside of any currently shown flyout/menu will close all currently shown flyout/menus in the cascade and place the new showing flyout/menu at the head of a new cascade.
     - Refactoring a lot of the event handling policy from MenuCommand.js into the Menu.js
     - More unit tests

There will be at least two more checkins before the complete feature is completed.
     Still left to do:
     - Enable new selection styling for 'flyout' typed MenuCommands to indicate which MenuCommand in a parent Menus has invoked the current open sub menu.
     - Enable smart positioning for cascading flyouts/menus.