ECG Signal v1.2

Added folder, figures, section, and code snippet

• plots/ for Processing Bio ECG and Filtering of an ECG Signal Corrupted by Power Supply Hum figures in README.md
• Moving Average Filter and Convolution Section in README.md
• Filtering of an ECG Signal Corrupted by Power Supply Hum: Code snippet using the MATLAB function designfilt in 60 Hz Interference and Filtered ECG Signals

Renamed MATLAB files

• Processing Bio ECG Signal: ecg_1.m → processing_bio_ecg.m
• Filtering of an ECG Signal Corrupted by Power Supply Hum: ecg_2.m → iir_ecg.m