daler/pybedtools — pull request #46 by jakebiesinger (2011-12-08 22:43:03+00:00)
Title: Allow negative indices in Interval slices

Slicing intervals with negative ranges doesn't work currently:

```python
import pybedtools
a = pybedtools.example_bedtool('a.bed')
e = a[0]
e[:5] # ok
e[2:-1] # returns empty list
```

This fix is the "proper" way to do it since python 2.3, see http://docs.python.org/release/2.3.5/whatsnew/section-slices.html

Also, when trying to run the test suite, I got relative path errors-- fixed using bedtools_dir.