Save time and bandwidth on SVN checkouts

Especially on bundles using clean-libraries it takes quite some time to download the repository, while with SVN it is not needed to download everything. There are two ways to speed this up:

For instance, checkout https://svn.cs.ru.nl/repos/clean-libraries/trunk/Libraries/TCPIP instead of https://svn.cs.ru.nl/repos/clean-libraries/trunk
Use svn export instead of checkout to discard versioning information

When building bundle-complete for a particular date, clean-libraries is downloaded many times, and with these changes we can win quite some time there.