Updated syn and quote to 0.15 and 0.6.

[azriel91]

Issue #25

Oh ya, assuming you're accepting this PR, do you want the rustfmt.toml deleted or kept?
rustfmt 0.99.5-nightly (90692a5 2018-09-26) panics with the values present

[azriel91]

Ready for review!
All tests (except the compile fail ones) pass; I'm super happy you've got so many automated tests, allows me the confidence to fearlessly hack away ⚔️

[azriel91]

Hiya, so I managed to fix the derive-partial-eq compile fail test, but the derive-copy-clone test is not possible to be fixed, as a custom derive is a proc_macro_derive, whereas only proc_macro_attributes can see derive(..)s: dtolnay/syn#433.

I've used this in a fairly large project (a game that uses Amethyst), and it works as expected. There is heavy usage of derivative in the gfx crate, which is where I discovered and fixed the tricky issues.

[mcarton]

Thanks you very much for this!
I have been meaning to do this for ever, but never had time to do it because there were so many changes.
I will remove the broken test as it is indeed not possible to get it to work any more.

[azriel91]

woo all good! Your code's high quality 👌 so it makes it easier to jump in.
fun fact, it was easier fixing the number of errors from 114 to 20, than from 2 to 0 😂