Added `module purge` step

See merge request !4

Added a comment that the environment must be "clean" (using `module purge`), which is not the case when entering a terminal via Jupyter

Pyenv kernel tutorial

See merge request !3

pyenv kernel tutorial: Removed any mention to changes in .bash_profile; Changed folder to ${PROJECT}/${USER}.

Pyenv kernel tutorial

See merge request guimaraes1/j4j_notebooks!1

minor fix for the HDF-Cloud, where ${KERNEL_SPECS_DIR} might not exist.

minor fix