Use short options

The BSD rm available on OS X doesn't understand the long options.
Add Vagrant configuration
Clean up Makefile
Use headings in the changelog

This way they can be linked on GitHub.
Move the library to the top of the Cabal file

It's the most important thing, after all.
Remove version constraint on base

It's going to be whatever GHC provides. Can't do anything about it.
Add GHCi configuration
Include all files in HPC
Use GNU-compatible options
Load the library in GHCi