Reflow the README to 80 columns and update a few bits for better consistency
Merge pull request #539 from tianon/consistent-readme

Reflow the README to 80 columns and update a few bits for better consistency
VBox guest additions. Refs #282
Update VBox Additions code with some minor changes (especially for cache-ability)

Also, this includes a hacky init script that bfirsh gets to take all the credit for that tries to mount `/Users` and/or `/c/Users`, since we can't run `VBoxService` proper (thanks to hairy issues with 32bit userspace of TCL; good times).