Use HTML parser/Fix typo.

Use HTML parser instead of manually parsing. Fix typo
in release names/versions.
Signed-off-by: Sandon Van Ness <sandon@inktank.com>
Allow codename instead of version for Ubuntu.

Let distroversion take a codename like quantal instead of
the version IE 12.10.


Signed-off-by: Sandon Van Ness <sandon@inktank.com>
Allow use of raw images denoted by .raw extension

Allow downburst to use raw disk images instead of our
normal compressed qcow2 images (for better performance).

The raw images are detected/set by their file-extension
which is .raw instead of .img.

Signed-off-by: Sandon Van Ness <sandon@inktank.com>