Make old nodes available in nightly build

[dietzc]

Currently, the nightly build only comprises the new set of nodes. However, the old nodes are used in many production environments and we shouldn't deprecate them as they comprise more functionality than the new ones. Please re-add.

[gab1one]

A quick look at:
https://github.com/knime-ip/knip-ilastik/tree/master/org.knime.knip.ilastik/src/org/knime/knip/ilastik/nodes/headless
shows that the master branch contains only the old nodes. Jenkins ships: https://community.knime.org/jenkins/job/org.knime.community.update-trunk/lastSuccessfulBuild/artifact/org.knime.community.update/plugins/org.knime.knip.ilastik_0.3.6.v201803131055.jar in the nightly update site.