Upgrade librabbitmq version to 0.4

[j16sdiz]

This fix issue #16 as well.

I have run this for a few hours on Debian Linux and it seems to work fine.

But there are few this I am not qualify to check:

1. Compile on other OS / Distro? I just hardcode it use select() (instead of detecting to epoll() support), guess this should be cross platform....
2. Any resource leak? In particular, I have removed a close(sockfd) because the new library does not expose the raw socket. According to this post, it should work. But it may need more careful review.

[keithf4]

I've created a 0.5.0_dev branch with this pull request incorporated. Also made it an actual extension update and fixed the config table to dump its data.

I've tested all the basic functionality of the included sql functions and things seem to be working. If anyone can provide a more thorough evaluation in a more realistic environment that would be great.

@marcelloceschia If you want to try and incorporate your ssl patch against this branch, please feel free.

[Godwottery]

I am currently testing this with 0.5.0 on Windows. Seems to be working.

[esatterwhite]

@j16sdiz Did you ever have any luck here? I know this is a bit out of date. I think librabbitmq is on 0.8 now