Make icon shadow adjustable

[moxwel]

Make the shadow adjustable through CLI arguments.

Example

python winLabeler.py "C:\example.png" --shadow 5

python winLabeler.py "C:\example.png" -sh 5

Add shadow with 5 gaussian filter (Image.shadow(alpha=50, sigma=5, x=0, y=0))

python winLabeler.py "C:\example.png"

No shadow