Pass list position to detail fragment

Use index instead of the item itself, it's faster and allows paged viewing
in the detail fragment.

Signed-off-by: Claudio Matsuoka <cmatsuoka@gmail.com>
Update tablet layout

Extend the item shadow to the area below the list view to keep the
separation between the list and detail areas.

Signed-off-by: Claudio Matsuoka <cmatsuoka@gmail.com>
Enable detail swiping

Details can now be swiped left/right in small screen devices (where
the detail fragment has its own activity).

Signed-off-by: Claudio Matsuoka <cmatsuoka@gmail.com>