bedtools version 2.23.0

New features.

1. Added -k option to the closest tool to report the k-closest features in one or more -b files.
2. Added -fd option to the closest tool to for the reporting of downstream features in one or more -b files. Requires -D to dictate how "downstream" should be defined.
3. Added -fu option to the closest tool to for the reporting of downstream features in one or more -b files. Requires -D to dictate how "downstream" should be defined.
4. @lindenb added a new split tool that will split an input file into multiple sub files. Unlike UNIX split, it can balance the chunking of the sub files not just by number of lines, but also by total number of base pairs in each sub file.
5. Added a new spacing tool that reports the distances between features in a file.
6. @jayhesselberth added a -reverse option to the makewindows tool that reverses the order of the assigned window numbers.

Bug fixes.

1. Fixed a bug that caused incorrect reporting of overlap for zero-length BED records. Thanks to @roryk.
2. Fixed a bug that caused the map tool to not allow -b to be specified before -a. Thanks to @semenko.
3. Fixed a bug in makewindows that mistakenly required -s with -n.