Fix weno to work with standard examples

Currently working examples

• advection + sine
• advection + bump
• burgers + sine
• burgers + gaussian
• euler + smooth
• euler + sod shocktube
• sr euler + sod shocktube
• sr euler + blast wave 1

Blast wave 2 test is not working, but none of the other methods is working in this case either. The overall quality of the weno implementation is also not good. Although I think the weno implementation together with the splitting technique is correct, the results are still very poor. But I don't see where the problem is ...

experiments/advection_bugner_gaussian/advection_bugner_gaussian_25.toml

+[Equation]
+type = "Advection"
+v = 1.0
+
+[Mesh]
+xrange = [-3.0, 3.0]
+CFL = 0.2
+N = 4
+K = 160
+
+[Output]
+variables       = [ "u", "flag" ]
+every_dt = 0.01
+aligned_times   = [ 0.05, 0.15, 0.20 ]
+
+[Grid]
+type = "LGL_lumped"
+
+[Evolution]
+tend = 0.3
+
+[Initialdata]
+type = "bugner gaussian"
+
+[TCI]
+type = "Minmod"
+
+[HRSC]
+type = "WENOReconstruction"
+order = 3