Part #1: get user input

User is to enter integer as indicated:
	0 -- rock
	1 -- paper
	2 -- scissors
	3 -- quit

Algorithm:

loop
	v <- what user enters
	on exception:
		print "You have to enter ..."
	if v is 0, 1, 2, or 3:
		break
	else:
		print "You have to enter ..."
endloop

print v
return v

Exceptions:
	name, type, syntax ...

def getuser():
	while True:
		try:
			v = input("Enter 0 (rock), 1 (paper), 2 (scissors), 3 (quit): ")
			v += 0;
		except EOFError:
			v = 3
		except (SyntaxError, NameError, TypeError):
			v = -1
		if 0 <= v and v <= 3:
			break
		print "You have to enter a 0, 1, 2, or 3 only"
	print "You pick", what(pick)
	return v