Remove ISU specific references and add to default css.

Removes site specific references to make more generic. Adds more
css to provide a more polished default. Removes common modules
from drupal-org.make. Updates README with small amount of install
instructions regarding missing common module dependencies in
drupal-org.make.
Merge pull request #3 from kevinchampion/genericize

Core: Remove ISU specific references and add to default css.