Clear up DelftBlue tutorial (#359)

* Clear up DelftBlue tutorial
A few minor clarifications to the DelftBlue part of the MPI tutorial.

* MPI tutorial: pip upgrade existing EMAworkbench installation

This makes sure users don't accidently keep using an older version if they installed it previously.

docs/source/indepth_tutorial/mpi-evaluator.ipynb

@@ -283,9 +283,9 @@
     "module load py-mpi4py\n",
     "module load py-pip\n",
     "\n",
-    "pip install --user ema_workbench\n",
+    "pip install --user --upgrade ema_workbench\n",
     "\n",
-    "mpiexec -n 1 python3 example_mpi_lake_model.py\n",
+    "mpiexec -n 1 python3 ema_example_model.py\n",
     "```\n",
     "\n",
     "Modify the script to suit your needs:\n",
@@ -340,13 +340,13 @@
     "\n",
     "Create a new directory for this tutorial, for example `mkdir ema_mpi_test` and then `cd ema_mpi_test`\n",
     "\n",
-    "Then, you want to send your Python file and SLURM script to DelftBlue. Open a **new** command line terminal, and then you can do this with `scp`:\n",
+    "Then, you want to send your Python file and SLURM script to DelftBlue. Make sure your files are all in one folder. Open a **new** command line terminal, `cd` in the folder where your files are, and then send the files with `scp`:\n",
     "\n",
     "```bash\n",
     "scp -J <netid>@student-linux.tudelft.nl ema_example_model.py slurm_script.sh <netid>@login.delftblue.tudelft.nl:/scratch/<netid>/ema_mpi_test\n",
     "```\n",
     "\n",
-    "Before scheduling the SLURM script, we first have to make it executable:\n",
+    "Now go back to your original cmd window, on which you logged in on DelftBlue. Before scheduling the SLURM script, we first have to make it executable:\n",
     "\n",
     "```bash\n",
     "chmod +x slurm_script.sh\n",