integrated all merchant data
able to detect which tabItem is selected in TabBarVC
add icon and splash PNG images
change welcome page to Windows8 magnet style
Welcome page can recognize gesture
extract SwipeVC as component of swiping images, which is loaded by WelcomeVC
customize setter of images to refresh image count.
send out click event to delegate
clean up WelcomeVC.
unify VC style to black&white