add an example of comparing the compressible solvers (#236)

also fix __repr__ of Pyro

Author: zingale

docs/source/compressible-rt-compare.ipynb

@@ -62,6 +62,7 @@ new ideas.
    :caption: Examples
    :hidden:
 
+   compressible-rt-compare.ipynb
    advection-error.ipynb
    compressible-convergence.ipynb
 

docs/source/index.rst

@@ -239,7 +239,10 @@ def single_step(self):
             tm_vis.end()
 
     def __repr__(self):
-        """ Return a representation of the Pyro object """
+        s = f"Pyro('{self.solver_name}')"
+        return s
+
+    def __str__(self):
         s = f"Solver = {self.solver_name}\n"
         if self.is_initialized:
             s += f"Problem = {self.sim.problem_name}\n"