Duplicate and unused images

[rdworth]

The following images are duplicates or unused and should be removed or renamed for consistency:

duplicates (remove):
base/i/bg-body-qunit.jpg
base/i/bg-body-sizzle.jpg
base/i/logo-qunit.png
base/i/logo-sizzle.png

unused (remove):
base/i/bg-footer.png
base/i/bg-title-shadow.png
base/i/footer-comp.png
base/i/logos-sponsors.png

inconsistent (rename):
base/i/logo-top-qunit.png -> base/i/logo-top-qunitjs.png
base/i/logo-top-sizzle.png -> base/i/logo-top-sizzlejs.png

[rdworth]

Further fix in b443934