Screed 1.0 Release Candidate Prep work

Right. So.

 - [ ] write screed release docs
 - [x] install/run versioneer
 - [ ] update relevant docs (known_issues, etc.)
 - [ ] make shiny new packages
 - [ ] do release?
add:

```
nosetests khmer --attr '!known_failing'
tar xzf screed*tar.gz
cd screed*
make dist
make test
```