Batchreader
This merge request introduces a new class called 'BatchReader' that facilitates reading of large number of wave files (or large individual files) by splitting the data up into batches of manageable size.
A new function for parsing date-time data from strings has been added to the data_handling module.
Some methods have been added to the AudioSignal and TimeStampedAudioSignal classes, including a new 'clip' method.
Unit tests have been implemented for (practically) all new features.