Better alignment for nested lists (fixes #25)

Currently, nested lists all align on the same left margin. Making them
nest properly was as simple as an alteration on their left-margin CSS
property. Hope that's sufficient.

Signed-off-by: David Celis <david@davidcelis.com>
Merge pull request #35 from davidcelis/fix-nested-lists

Better alignment for nested lists (fixes #25)