remove some unused parameters from compressible_sdc (#333)

Author: zingale

pyro/compressible_sdc/_defaults

@@ -15,10 +15,6 @@ delta = 0.33              ; flattening delta parameter
 
 cvisc = 0.1               ; artificial viscosity coefficient
 
-limiter = 2               ; limiter (0 = none, 1 = 2nd order, 2 = 4th order)
-
-temporal_method = RK4     ; integration method (see mesh/integration.py)
-
 grav = 0.0                ; gravitational acceleration (in y-direction)
 
 riemann = CGF