pip install issue on crib

[geek-yang]

When trying to install pystemmusscope on crib with pip install pystemmusscope I got this error:

FileNotFoundError: [Errno 2] No such file or directory: '/usr/bin/pip'

This is because pip is install at /usr/local/bin/pip.

By adding the --user flag pip install --user pystemmusscope, this will work. It would be better if we add an extra instruction in the installation_instructions.md, for those who are not familiar with the cluster system.

STEMMUS_SCOPE_Processing/docs/installation_instructions.md

Lines 39 to 43 in 8eb8c73

	Open a jupyter notebook and run the code below in a cell:
	```python
	!pip install pystemmusscope
	```