ubuntu: Obtaining the source for an Ubuntu release

Signed-off-by: Fudong Bai <fudongbai@gmail.com>
ubuntu: Build Environment for kernel

If you've not built a kernel on your system before, there are some
packages needed before you can successfully build.

Signed-off-by: Fudong Bai <fudongbai@gmail.com>
ubuntu: cleanup install.sh

Signed-off-by: Fudong Bai <fudongbai@gmail.com>