v3.4.0

• Adds EDF+C support for edf2mit
• Improves speed of resample_ann
• Allows negative annotation subtypes
• Adds rr2ann
• Updates to Python 3.6+
• Adds sharex and sharey to plot_items
• Adds wfdbdesc
• Adds wfdbtime
• Adds conversion for CSV to WFDB-annotations
• Adds rdedfann
• Adds information about WFDB header format in wfdb/io/_header.py
• Adds mrgann
• Adds sigavg