Install of raring kernel on precise

Docker works best on the 3.8 kernel.
Precise comes with a 3.2 kernel, so we need to upgrade it.
Merge pull request #14 from daniellawrence/raring_kernel_for_precise

Install of raring kernel on precise
don't need to explicitly pass params
allow disabling managin the kernel
validate the manage_kernel option
document all the new options
bump version number
fix spacing in README
bump version number
add syntax checking
Merge pull request #15 from garethr/upstart-on-reboot

modify the container upstart scripts to start after docker
bump version number
Make the apt::source optional, for folks who run their own apt mirrors.