moving s_center.py back to center.py
moving s_center.py back to center.py

lsaffre/lino,khchine5/lino,khchine5/lino,lino-framework/lino,lsaffre/lino,lino-framework/lino,lino-framework/lino,lsaffre/lino,khchine5/lino,lino-framework/lino,lsaffre/lino,khchine5/lino,lino-framework/lino,khchine5/lino,lsaffre/lino