Feature/data structure refactor

Context

Created and separated data structures (Event, Channel, Pulse) that will be used throughout the project. Separated static functions and created a WaveformStatistic file.

Summary

A Channel class contains a single waveform and a vector of pulses that belongs to that waveform. An Event class contains a vector of waveforms. The pulse structure was extracted and put into a separate file. Static functions were removed from Waveform class and given a new file.