[BUG] left click for image movement also places point

[lavender22]

Describe the bug
When using the movement controls in the "pick_points" function, any click on the image places a reference coordinate. The movement controls require click and dragging for zooming etc and it is unclear how to remove points once placed.

To Reproduce
Steps to reproduce the behavior:

1. run "pixel_sample_coords = pick_points(imagepath)"
2. "pan axis with left mouse, zoom with right" - left click places point when trying to pan
3. "zoom to rectangle" movement, left click and drag places point when trying to zoom

Expected behavior
Being able to zoom and pan within the image without placing points OR being able to easily delete points if misplaced.

Environment:

• OS: Windows
• Python Version [3.7.6]
• Autopew Version [0.1.1+24.g7147a2a]

[morganjwilliams]

As an idea for improving this point-picking window, we could use the existing functionality of e.g. bokeh