Fix for the NOE analysis for the peak intensity parameters.
This relates to bug #21863 (https://gna.org/bugs/?21863), the grace.write user function not being
able to write ref/sat plots as described in sample script noe.py.
The 'ref' and 'sat' parameters have been replaced by the 'intensities' dictionary data structure a
long, long time ago. Therefore they have been eliminated and replaced by the 'intensities'
definition.
