Merge signed-int into master

[tarcieri]

Lands the signed Int functionality on the master branch, effectively stabilizing the functionality prior to the v0.6 release

[tarcieri]

Looks like a small merge conflict in non_zero.rs

[erik-3milabs]

Looks like a small merge conflict in non_zero.rs

I know how to merge this, but when I press "resolve conflicts", I'm greeted with a 404. Chances are I'm not allowed to look at that screen because I don't have appropriate rights?

[tarcieri]

I tried to merge this locally and ran into some very weird errors.

@erik-3milabs What did your resolution look like? Can you push the commit up to a branch?

[tarcieri]

Oh I see, it's #710 that's causing problems. I guess we can't just merge things as-is.

[erik-3milabs]

@tarcieri I have both merged signed-int with master and rebased it onto master. Feel free to have a look and determine the solution you deem most appropriate. Let me know what I can do to help out!

[tarcieri]

@erik-3milabs can you open a PR for the merged-signed-int branch which can replace this one? (also, it looks like it needs rustfmt)

[erik-3milabs]

@erik-3milabs can you open a PR for the merged-signed-int branch which can replace this one? (also, it looks like it needs rustfmt)

@tarcieri done. It is up now as #730.