If a plugin has been set before, run() would previously clobber it. Now this will preserve prior plugins
If a plugin has been set before, run() would previously clobber it. Now this will preserve prior plugins

krishauser/Klampt,krishauser/Klampt,krishauser/Klampt,krishauser/Klampt,krishauser/Klampt,krishauser/Klampt