Add du to Makefile
Remove du from to-do list
Get basic functionality to work
Getting it to display the correct directory size
Implemented a few more options
Add formatting-related logic
Correctly calculate file size using number of blocks
Adding partial support for formatting time
Fixing time format string
Merge branch 'add-du' of https://github.com/derekchiang/coreutils into add-du

Conflicts:
	README.md
Fix du, which closes #46, and id when not compiling on Linux
Merge pull request #99 from Arcterus/du-and-id-fixes

du and id fixes