Fix bookstore demo layout
Fix bookstore demo layout

Setting the bottom property to 0 binds the details composite to the
bottom edge of the book details page and suppresses the tab folder
below.

This bug appears *not* to be related to the bottom property bug in
the Android layout implementation.

Change-Id: I7d62606c67d2ecc02e05b44ff888d4c977f77d49
Signed-off-by: Ralf Sternberg <787dd4af1300cc812dc7227f86eda8477264a73f@eclipsesource.com>
eclipsesource/tabris-js,moham3d/tabris-js,softnep0531/tabrisjs,eclipsesource/tabris-js,softnep0531/tabrisjs,pimaxdev/tabris,mkostikov/tabris-js,paulvi/tabris-js,pimaxdev/tabris,eclipsesource/tabris-js,mkostikov/tabris-js,moham3d/tabris-js