split: Initial import

Signed-off-by: Akira Hayakawa <ruby.wktk@gmail.com>

----

Here is a split implementation.

I have a subsidiary project for testing (https://github.com/akiradeveloper/rust-split) where I compare my split with GNU split as a reference implementation in a way like QuickCheck.

Quick look at the performance says my split is twice slower than GNU one. Not desperate, and I will improve this later.
> In split/split.rs:
> 
>> @@ -0,0 +1,278 @@
>> +#![crate_id(name="mkdir", vers="1.0.0", author="Akira Hayakawa")]
> 
> The name here is wrong.

Thanks.

Fixed

- Akira