add conda-forge to installation instructions

Now that POT is in conda-forge (conda-forge/staged-recipes#3332 / https://github.com/conda-forge/pot-feedstock/), might as well put that in the installation instructions.

Note that it's available on Windows too, and [this basic test](https://github.com/conda-forge/pot-feedstock/blob/master/recipe/run_test.py) at least runs.

Author: djsutherland

README.md

@@ -22,28 +22,31 @@ Some demonstrations (both in Python and Jupyter Notebook format) are available i
 
 ## Installation
 
-The Library has been tested on Linux and MacOSX. It requires a C++ compiler for using the EMD solver and rely on the following Python modules:
+The library has been tested on Linux and MacOSX. It requires a C++ compiler for using the EMD solver and relies on the following Python modules:
 
 - Numpy (>=1.11)
 - Scipy (>=0.17)
 - Cython (>=0.23)
 - Matplotlib (>=1.5)
 
-
-Under debian based linux the dependencies can be installed with
+If you use the Anaconda python distribution, POT is available in [conda-forge](conda-forge.github.io). To install it and the required dependencies:
 ```
-sudo apt-get install python-numpy python-scipy python-matplotlib cython
+conda install -c conda-forge pot
 ```
 
-To install the library, you can install it locally (after downloading it) on you machine using
+Otherwise, under Debian-based Linux the dependencies can be installed with:
 ```
-python setup.py install --user # for user install (no root)
+sudo apt-get install python-numpy python-scipy python-matplotlib cython
 ```
 
-The toolbox is also available on PyPI with a possibly slightly older version. You can install it with:
+You can then install the toolbox through PyPI with:
 ```
 pip install POT
 ```
+or get the very latest version by downloading it and then running:
+```
+python setup.py install --user # for user install (no root)
+```
 
 After a correct installation, you should be able to import the module without errors:
 ```python