Road to 1.0

[thejpster]

What do we need to do to put out a 1.0 release? One assumes we at least need an embedded-hal 1.0 (rust-embedded/embedded-hal#177)

[kellda]

I think something that should be done on the next breaking release is using the "sealed trait" pattern for *Pin traits.

I.e. having a private trait Sealed and requiring *Pin: Sealed. This would be better than (and should be done instead of) writing "DO NOT IMPLEMENT THIS TRAIT" in the docs.

Btw, why are internal macros such as uart_hal_macro and uart_pin_macro exposed in the API ?

[thejpster]

Happy to see a PR.

Macros I think are shared between tm4c123 and 129 and hence exported from tm4c common.