Benchmark "hohlcont" : Linear Elasticity (x-y-coordinates) with contact (Signorini-problem)

Material coefficients:	E	nu
	100000.	0.3
volume force :	f
	(0,-6000)	above
Boundary conditions:
contact:	y+u^2(x,y) > 0
Dirichlet-type:	u^1 = 0	at x=0 (symmetry!)

contact pressure (versus x-coordinates):

Typical behavior of estimated relative error:
(Das typische Verhalten des geschaetzten rel. Fehlers) (Legend)

here some RUNs with times / iteration numbers / etc.