Removal of throbber.src

[Stefan Knorr]

Hello Thomas, Michael,

AFAIK, LibO uses a throbber in its extension manager, e.g. when looking
for extension updates. I believe the application update checker also
uses a throbber.
I can't really say if that's the one you are trying to remove (I think
there were multiple throbber directories)... but, as Michael says,
images.zip tends to become stale on subsequent builds.

Stefan.