Merge branch 'deny-double-login' into 'master'

More robust double login checking

See merge request !4

server/deny.bashrc

 
-if [ $(w | grep $LOGNAME | wc -l) -gt 1 ]; then
+if [ $(who | grep -cw ^$LOGNAME) -gt 1 ]; then
   echo This account is already in use, exiting.
   exit
 fi