Update README to include amrex version. Comments in input file for amrex version.

Author: hctorres

swm_AMReX/inputs

@@ -1,13 +1,20 @@
-nx = 64
-ny = 64
+# Number of cells on each direction
+nx = 64 
+ny = 64 
 
+# Cell size in each direction
 dx = 100000
 dy = 100000
 
+# Mesh will be broken into chunks of up to max_chunk_size
 max_chunk_size = 100000
 
+# Number of time steps to take
 n_time_steps = 4000
 
+# Size of time step
 dt = 90
 
+# How often to write a plotfile
+# Optional. If left out no plot files will be written.
 plot_interval = 100