Persistent Figure

A function to persistently draw a figure window at the same position on the screen.

p_figure is a wrapper around imshow to draw and keep the figure window position and size from resetting with each call.
See https://github.com/lordloh/persistent-figure/blob/master/README.md
# Usage:
```
fig1=p_figure(im)
```
Now move the figure to different screen or resize.
```
fig1=p_figure(im2,'fig_h',fig1)
```
The new image is displayed in the same figure window without changing the position.