With this change, StyleManager will first trigger an internal signal
that is picked up by all Controls, then will emit StyleChanged to
signal to the application that the theme or system fonts have changed
and that the styling has completed.
Change-Id: I54ced7ad5ffc08bf5e55c9895be03848bea6b7a6 Signed-off-by: David Steele <david.steele@samsung.com>