New design is bound to BrowserRootCategories collection

New design is bound to BrowserRootCategories collection. There are some bugs but we have something to show. Works correctly for Geometry category. Possible too long names of some functions. For example: `Geometry.Cuboid`.

@Benglin, please review.
@Benglin, purpose of this code is to find width of class (in other words subcategory) not `StandardPanel`. We are using this width later in calculation of position of `StandardPanel` in function `OrderListItems()`.

So this code is correct.