rexport std_prelude in prelude

[vitiral]

https://github.com/vitiral/std_prelude

I personally feel like this makes writing quick things in rust much more ergonomic.

I'm openeing a separate issue for a discussion on the overal design goals of this lib

[killercup]

Wow, just read through your docs. This is impressive!

I want to add our re-exports a bit more deliberate, though. I'll write a bit more in #19.

[killercup]

tl;dr from #19: I'm good with re-exporting some traits and useful macros but would rather add some abstraction around common use cases instead of giving our users access to everything.

[vitiral]

closing per #19