updated difficulty and prior skill
Merge branch 'master' of https://github.com/dionysio/SlepemapyAnalysis

Conflicts:
	drawable.py
	graph.py
	graphs-global.py
	graphs-place.py
	graphs-user.py
	inputoutput.py
	libs/analysis.py
	libs/map.py
	main.py
	maps-place.py
	maps-user.py