Rename README.txt to README.md

Author: barbourww

README.txt README.mdREADME.txt renamed to README.md

@@ -14,4 +14,4 @@ Use the `requirements.txt` file included in this repository to set up a Python e
 The example trajectory data snippet should be downloaded from http://vu.edu/laddms-data-snippet. This data file should be placed in the same directory as the tutorial notebook and other files.
 
 ## Running the tutorial
-Open the tutorial notebook `basic_data_tutorial.ipynb` by activating the Python environment (`conda activate laddms_tutorial`) and running Jupyter Lab notebook server with the terminal command `jupter lab`.
+Open the tutorial notebook `basic_data_tutorial.ipynb` by activating the Python environment (`conda activate laddms_tutorial`) and running Jupyter Lab notebook server with the terminal command `jupter lab`.