configure.ac: Print results

Print results after configure.
vcs: Use find() instead of index()

If the substring is not found, the index method will raise an exception,
find() on the other hand just returns a negative integer.
bdiff: Use latest src for local previous component when no override is found

If previous component was a local override and the directory was
removed, we can't run git log and diffstat so we change the previous
component src to the latest component's temporarily.
buildlive: UEFI support

UEFI support for x86_64 live images. When gummiboot is not found,
no UEFI support will be available on generated images.

This might be broken, it's not tested because I can't build gummiboot
on Ubuntu 12.10.

Issue: #27
build: Installed tests support

Install tests for components.

Closes #31