Source appscale_tools.sh in appscale_install_functions

The appscale_tools.sh file is installed when the Vagrant VM is
provisioned.  It contains the keygen function that is also needed when
building appscale-tools with the debian/appscale_build.sh script.  In
order to accommodate both needs, source the appscale_tools.sh script
from appcale_install_functions.sh
Test to make sure this is run on a lucid box.

Lucid is currently the only supported OS.
Updated appscale_build.sh to call appscale_install.sh

Removed install files for other flavors since they are not supported
anyway.