Add screen shots test for UI
Add screen shots test for UI

To use this, for example

bepasty.conf should include this PERMISSIONS config.

	PERMISSIONS = {
	    'foo': 'admin,list,create,read,delete',
	}

run,

	$ BEPASTY_CONFIG=$(pwd)/bepasty.conf bepasty-server
	$ cd bepasty-server/src/bepasty/tests
	$ pytest -s -vv screenshots.py

this makes "screenshots/" directory for screenshot images.

bepasty/bepasty-server,bepasty/bepasty-server,bepasty/bepasty-server,bepasty/bepasty-server