revise installation and contribution instructions

I try to cleanly separate between information that should be part of the
Kwant source distribution (that is tied to a particular version of
Kwant), and generic information that is best presented on the website.

CONTRIBUTE.rst

@@ -9,76 +9,6 @@ leaving room for growth, and plan to keep extending it.
 
 External contributions to Kwant are highly welcome.  You can help to advance
 the project not only by writing code, but also by reporting bugs, and
-fixing/improving the documentation.  A `mailing list
-<http://kwant-project.org/community.html>`_ is available for discussions.
-
-If you have some code that works well with Kwant, or extends it in some useful
-way, please consider sharing it.  Any external contribution will be clearly
-marked as such, and relevant papers will be added to the list of
-:doc:`suggested acknowledgements <citing>`.  The complete development history
-is also made available through a `web interface
-<http://git.kwant-project.org/kwant>`_.  If you plan to contribute, it is best
-to coordinate with us in advance either through the `mailing list
-<http://kwant-project.org/community.html>`__, or directly by `email
-<mailto:authors@kwant-project.org>`_ for matters that you prefer to not discuss
-publicly.
-
-Reporting bugs
---------------
-
-If you encounter a problem with Kwant, first try to reproduce it with as simple
-a system as possible.  Double-check with the documentation that what you
-observe is actually a bug in Kwant. If you think it is, please check whether
-the problem is already known by searching the `mailing list
-<http://kwant-project.org/community.html>`__.
-
-If the problem is not known yet, please email a bug report to the `Kwant mailing
-list <http://kwant-project.org/community.html>`__. A report should contain:
-
-* The versions of software you are using (Kwant, Python, operating system, etc.)
-
-* A description of the problem, i.e. what exactly goes wrong.
-
-* Enough information to reproduce the bug, preferably in the form of a simple
-  script.
-
-How to contribute
------------------
-
-We use the version control system `Git <http://git-scm.com/>`_ to coordinate the
-development of Kwant.  If you are new to Git, we invite you to learn its basics.
-(There's a plethora of information available on the Web.)  Kwant's Git
-repository contains not only the source code, but also all of the reference
-documentation and the tutorial.
-
-It is best to base your work on the latest version of Kwant::
-
-    git clone http://git.kwant-project.org/kwant
-
-Then you can modify the code, and build Kwant and the documentation as described
-in the :doc:`installation instructions <install>`.
-
-Some things to keep in mind:
-
-* Please keep the code consistent by adhering to the prevailing naming and
-  formatting conventions.  We generally follow the `"Style Guide for Python
-  Code" <http://www.python.org/dev/peps/pep-0008/>`_ For docstrings, we follow
-  `NumPy's "Docstring Standard"
-  <http://github.com/numpy/numpy/blob/master/doc/HOWTO_DOCUMENT.rst.txt>`_ and
-  `Python's "Docstring Conventions"
-  <http://www.python.org/dev/peps/pep-0257/>`_.
-
-* Write tests for all the important functionality you add.  Be sure not to
-  break existing tests.
-
-A useful trick for working on the source code is to build in-place so that there
-is no need to re-install after each change.  This can be done with the following
-command ::
-
-    python setup.py build_ext -i
-
-The ``kwant`` subdirectory of the source distribution will be thus turned into
-a proper Python package that can be imported.  To be able to import Kwant from
-within Python, one can either work in the root directory of the distribution
-(where the subdirectory ``kwant`` is located), or make a (symbolic) link from
-somewhere in the Python search path to the the package subdirectory.
+fixing/improving the documentation.  Please see the `Kwant website
+<http://kwant-project.org/community>`_ for information on how to get in touch
+with the Kwant community.