MNT: convert README to markdown

Thanks, pandoc!

README.md

@@ -0,0 +1,34 @@
+[![image](https://zenodo.org/badge/51149109.svg)](https://zenodo.org/badge/latestdoi/51149109)
+
+# About
+
+`pwtools` is a Python package for pre- and postprocessing of atomistic
+calculations, mostly targeted to [Quantum
+Espresso](http://www.quantum-espresso.org), [CPMD](http://www.cpmd.org),
+[CP2K](http://cp2k.org) and [LAMMPS](http://lammps.org). It is almost,
+but not quite, entirely unlike [ASE](https://wiki.fysik.dtu.dk/ase),
+with some tools extending
+[numpy](http://www.numpy.org)/[scipy](http://www.scipy.org). It has a
+set of powerful parsers and data types for storing calculation data. See
+the [feature
+overview](http://elcorto.github.io/pwtools/written/features.html) for
+more.
+
+The [dcd
+code](https://github.com/elcorto/pwtools/blob/master/src/pwtools/dcd.py)
+is now part of [ASE](https://wiki.fysik.dtu.dk/ase)'s [dcd reader for
+CP2K files](https://gitlab.com/ase/ase/blob/master/ase/io/cp2k.py).
+[Thanks](https://gitlab.com/ase/ase/merge_requests/1109)!
+
+# Documentation
+
+Have a look at [the docs](http://elcorto.github.io/pwtools). Quick start
+instructions can be found in [the
+tutorial](http://elcorto.github.io/pwtools/written/tutorial.html). Many
+examples, besides the ones in the doc strings are in [the
+tests](https://github.com/elcorto/pwtools/tree/master/test).
+
+# Install
+
+See the [install
+docs](http://elcorto.github.io/pwtools/written/install.html).

setup.py

@@ -34,7 +34,7 @@
 
 
 here = os.path.abspath(os.path.dirname(__file__))
-with open(os.path.join(here, "README.rst")) as fd:
+with open(os.path.join(here, "README.md")) as fd:
     long_description = fd.read()