## Introduction
Before we move container scheme to ready we need to have both the `colorScheme` and `typographyScheme` nonnull. By making colorScheme and typographyScheme of MDCContainerScheming nonnull, clients will reduce the amount of conditional checks required in their apps and reduce a category of potential errors (accidentally passing nil to a nonnull parameter).
## The problem
Both `colorScheme` and `typographyScheme` were nullable in the container scheme making it harder for clients to use the container scheme throughout their app on non Material UIElements, i.e. UIView.backgroundColor
## The fix
Make both of these properties nonnull.
## Additional work
- [x] I had to update the swift examples to not be optional and I additionally removed the nil checks from the ObjC examples.
