Clean up README.md
Remove trailing whitespace in README.md
Add Arch instructions (merged from GH-35).

Thanks @thiderman!
Change Ubuntu 12.04 to Ubuntu/Debian in README.md

That should work in most versions of Ubuntu and Debian.
Add modeline with tw per @ashleyh's suggestion
Fix anchors
Fix previous commit
Merge branch 'master' into pr36

Conflicts:
	README.md
Merge branch 'pr36'

Conflicts:
	README.md