Merge pull request clawpack#90 from katrinleinweber/patch-1

Hyperlink DOIs to preferred resolver

notebooks/pyclaw/Stegotons.ipynb

@@ -392,11 +392,11 @@
    "source": [
     "Zoom in on one of the waves above; they have an interesting shape!  Here are some other things to try, off the top of my head:\n",
     "\n",
-    "- How does the **magnitude of the impedance variation** affect the waves?  What if the impedance is constant?  What if it changes only a little? (see [this paper](http://dx.doi.org/10.4310/CMS.2012.v10.n3.a7) for an explanation)\n",
+    "- How does the **magnitude of the impedance variation** affect the waves?  What if the impedance is constant?  What if it changes only a little? (see [this paper](https://doi.org/10.4310/CMS.2012.v10.n3.a7) for an explanation)\n",
     "- What happens if some random perturbations are added to the medium?\n",
     "- Try isolating two of the solitary waves and then supplying them as an initial condition, and let the taller one overtake the shorter.  What happens when they interact (see the original paper of LeVeque and Yong for some discussion)\n",
     "\n",
-    "You can also look at multi-dimensional waves like these, but you'll want to run PyClaw in parallel (not in the notebook) to do so.  Take a look at [this paper](http://dx.doi.org/10.1007/s10915-013-9747-3) and some preprints listed [here](http://numerics.kaust.edu.sa/publications.html)."
+    "You can also look at multi-dimensional waves like these, but you'll want to run PyClaw in parallel (not in the notebook) to do so.  Take a look at [this paper](https://doi.org/10.1007/s10915-013-9747-3) and some preprints listed [here](http://numerics.kaust.edu.sa/publications.html)."
    ]
   },
   {