Re-add stamp images, add more holopads

Changes:
1) Re-adds stamp images.
2) Adds a stamp image for Central Command (used by the fax and Nanotrasen Representative), courtesy of Mr. W (WJohn).
3) Adds many more AI holopads to the station to give AI's a better opportunity to interact with the crew through them.
4) Fixes the roboticist's PDA skin.
5) The vault door now unlocks when the Blob almost reaches critical mass, and CentComm sends the report to arm the nuke.