[Fixed] a vendor to be considered empty when nothing is for sale (rather
than when nothing is on the vendor)
[Fixed] empty vendors will no longer be able to be registered on the
planetary map

Change-Id: I81e20b37f146f9ce4b35ee61ad3a818ff6416ab0
Merge "[Fixed] a vendor to be considered empty when nothing is for sale (rather than when nothing is on the vendor) [Fixed] empty vendors will no longer be able to be registered on the planetary map" into unstable