Added to "related tools", seemed the most appropriate place for now.

added macports as an option for installing bedtools on mac os x.

* capability

Fixed typo

-v on 3rd example too

add -v to example

Fixed sort command syntax on line 18

The UNIX sort command was not correct.
I fixed it so that the numerical sort was only applied to the second column.

The header for the -d option says '-hist', I edited the heading to say '-d' instead.