Make L_c smaller, use more homotopy steps

These are the values used in the Sander/Neff/Birsan paper on planar Cosserat shells.

cosserat-continuum-twisted-strip.parset

@@ -15,7 +15,7 @@ numLevels = 1
 #############################################
 
 # Number of homotopy steps for the Dirichlet boundary conditions
-numHomotopySteps = 12
+numHomotopySteps = 24
 
 # Tolerance of the trust region solver
 tolerance = 1e-8
@@ -70,7 +70,7 @@ lambda = 2.1796e+09
 mu_c = 0
 
 # Length scale parameter
-L_c = 0.002
+L_c = 2e-6
 
 # Curvature exponent
 q = 2