Make a release

[kamalmarhubi]

The last release was over two months ago, and a lot of new APIs have been added, as well as bumping libc to 0.2.x. Not sure whether this should be a 0.4.3 or a 0.5.0 release. The changes that make me think it might be better as 0.5.0 are:

• a number of flags became bitflags, changing argument types (though maybe not calling code?), eg in Convert MSG_ flags to bitflags! type. #256, More bitflags #253
• the type of SigAction::new changed: Account for the different signal handler types. #241

A concern: we have #230 that has been dormant pending discussion in #221 (also dormant!). Depending on when and how that is resolved, it could be we'll have another backwards incompatible change fairly soon. I still think making a release sooner than later is worthwhile.

[arcnmx]

I'd say the libc change bumps it up to 0.5.0 alone. There've been quite a few changes all around, it certainly warrants it. If there's a 0.7.0 a few weeks later then so be it.

[kamalmarhubi]

That makes sense. Now we need to figure out how to make a release... @carllerche, hi!

[kamalmarhubi]

We have a 0.5.0!