Update trace to match the new APIs available in recent TRAPpy versions
Created by: derkling
This series is almost just a cleanup of the Trace module to align its code the most recent versions of TRAPpy.
The series removes the internal trace_data dictionary, which was previously used to map DataFrame to a short and handy name. We use now standard tarcepoint names to access DataFrames collected from a trace, which can be obtained via Trace.df() not before having checked that they exists via Trace.hasEvents().
Appreciated if @JaviMerino can give it a look. Maybe a better interface can be used to wrap the TRAPpy FTrace module? Consider that technically all the features in that Trace module can be migrated directly to TRAPpy. What we do here is mainly DataFrame post-processing, sometimes on events which are not pre-registered in TRAPpy.