Create an iframe container for app demo

Usage

app_container(url, deps = FALSE, skin, color = NULL, landscape = FALSE)

url: app URL.
deps: Whether to include marvel device assets. Default to FALSE. The first occurence must set deps to TRUE so that CSS is loaded in the page.
skin: Wrapper devices.
color: Wrapper color. Only with iphone8 (black, silver, gold), iphone8+ (black, silver, gold), iphone5s (black, silver, gold), iphone5c (white,red , yellow, green, blue), iphone4s (black, silver), ipadMini (black, silver) and galaxyS5 (black, white).
landscape: Whether to put the device wrapper in landscape mode. Default to FALSE.