Allow sourcing of setup.sh from other directories

* only works for Bash shell; warning for others

setup.sh

-export TAPASCO_HOME=$PWD
+if [[ "-bash" == $0 ]]; then
+	export TAPASCO_HOME=`dirname ${BASH_SOURCE[0]} | xargs realpath`
+else
+	echo "WARNING: non-bash shell; need source setup.sh from the TaPaSCo root dir!"
+	export TAPASCO_HOME=$PWD
+fi
+echo "TAPASCO_HOME=$TAPASCO_HOME"
 export PATH=$TAPASCO_HOME/bin:$PATH
 export MANPATH=$MANPATH:$TAPASCO_HOME/man
-# source ~/vivado_15.sh
-sbt assembly