updated readme

README.md

-ias root:
+as root:
+
 yum install libXScrnSaver
 
 as user:
+
 python -m pip install --upgrade pip  setuptools wheel
+
 python -m  pip install Cheetah3
+
 python -m  pip install xlrd==2.0.1
+
 python -m  pip install openpyxl
+
 python -m pip install pysimplegui
 
 Install pyGen:
+
 git clone git@git.ia2.inaf.it:gino.tosti/pygen.git
 
+
 python setup.py bdist_wheel
+
 python -m pip install dist/GenDevice-0.1-py3-none-any.whl