Add building and fmt on travis

[TeXitoi]

To check that we compile on a set of different rust version, and that our formating is consistent, I propose to check on travis that the crate and its examples are building, and that our formating comply with rustfmt.

If it's OK, I can propose a PR for that.

[therealprof]

@TeXitoi We will definitely have Travis CI (as we do for the other -hal crates in this organisation). It's not in at the moment due to the USB SNAFU which means it does not fully compile yet.

[TeXitoi]

I don't get it, right now, Cargo.toml point to japaric's stm32f103xx crate, so it should compile, no?

[TeXitoi]

@therealprof can you add an issue about this SNAFU problem with some explanations to be able to follow the works on this subject? Thanks.

[therealprof]

@TeXitoi Please find it in #3 .

[TeXitoi]

@therealprof thanks

[therealprof]

@TeXitoi You're now a collaborator on this repository (I hope).

[TeXitoi]

Yes, thanks to @adamgreig for the invitation on stm32-rs org!

[therealprof]

I don't get it, right now, Cargo.toml point to japaric's stm32f103xx crate, so it should compile, no?

That's just a dev dependency and shouldn't even be there...

[TheZoq2]

I think this can be closed now thanks to #208 and #207