Update Readme badges and instructions (#346)

Author: rrjbca

README.rst

@@ -2,7 +2,7 @@
 SkyPy: A package for modelling the Universe
 ===========================================
 
-|Zenodo Badge| |Astropy Badge| |Test Status| |Coverage Status| |PyPI Status| |Anaconda Status| |Documentation Status|
+|PyPI| |conda-forge| |Read the Docs| |GitHub| |Codecov| |Zenodo|
 
 This package contains methods for modelling the Universe, galaxies and the Milky
 Way. Also included are methods for generating observed data.
@@ -43,35 +43,28 @@ To install using conda_:
 
     $ conda install -c conda-forge skypy
 
-You can test your SkyPy intallation using pytest_:
-
-.. code:: bash
-
-    $ pytest --pyargs skypy
-
 The SkyPy library can then be imported from python:
 
 .. code:: python
 
     >>> import skypy
-    >>> help(skypy)
 
 SkyPy has a number of optional dependencies which can be installed separately.
 One of these is `skypy-data`_ which contains data such as photometric bandpasses
 required for some calculations in SkyPy. This can be installed with:
 
 .. code:: bash
-    
-    pip install skypy-data@https://github.com/skypyproject/skypy-data/archive/master.tar.gz
+
+    $ pip install skypy-data@https://github.com/skypyproject/skypy-data/archive/master.tar.gz
 
 SkyPy also has a driver script that can run simulation pipelines from the
 command line. The `skypyproject/examples`_ repository contains sample
 configuration files that you can clone and run:
 
 .. code:: bash
 
-    git clone --depth 1 -b v$(skypy --version) https://github.com/skypyproject/examples.git
-    skypy examples/mccl_galaxies.yml --format fits
+    $ git clone --depth 1 -b v$(skypy --version) https://github.com/skypyproject/examples.git
+    $ skypy examples/mccl_galaxies.yml --format fits
 
 .. _PyPI: https://pypi.org/project/skypy/
 .. _conda-forge: https://anaconda.org/conda-forge/skypy
@@ -95,56 +88,21 @@ in the `Code of Conduct`_.
 .. _Contributor Guidelines: CONTRIBUTING.md
 .. _Code of Conduct: CODE_OF_CONDUCT.md
 
-**Imposter syndrome disclaimer**: We want your help. No, really.
-
-There may be a little voice inside your head that is telling you that you're not
-ready to be an open source contributor; that your skills aren't nearly good
-enough to contribute. What could you possibly offer a project like this one?
-
-We assure you - the little voice in your head is wrong. If you can write code at
-all, you can contribute code to open source. Contributing to open source
-projects is a fantastic way to advance one's coding skills. Writing perfect code
-isn't the measure of a good developer (that would disqualify all of us!); it's
-trying to create something, making mistakes, and learning from those
-mistakes. That's how we all improve, and we are happy to help others learn.
-
-Being an open source contributor doesn't just mean writing code, either. You can
-help out by writing documentation, tests, or even giving feedback about the
-project (and yes - that includes giving feedback about the contribution
-process). Some of these contributions may be the most valuable to the project as
-a whole, because you're coming to the project with fresh eyes, so you can see
-the errors and assumptions that seasoned contributors have glossed over.
-
-Note: This disclaimer was originally written by
-`Adrienne Lowe <https://github.com/adriennefriend>`_ for a
-`PyCon talk <https://www.youtube.com/watch?v=6Uj746j9Heo>`_, and was adapted by
-SkyPy based on its use in the README file for the
-`MetPy project <https://github.com/Unidata/MetPy>`_.
-
-.. |Zenodo Badge| image:: https://zenodo.org/badge/221432358.svg
-   :target: https://zenodo.org/badge/latestdoi/221432358
-   :alt: DOI of Latest SkyPy Release
-
-.. |Astropy Badge| image:: http://img.shields.io/badge/powered%20by-AstroPy-orange.svg?style=flat
-    :target: http://www.astropy.org
-    :alt: Powered by Astropy Badge
-
-.. |Test Status| image:: https://github.com/skypyproject/skypy/workflows/Tests/badge.svg
-    :target: https://github.com/skypyproject/skypy/actions
-    :alt: SkyPy's Test Status
-
-.. |Coverage Status| image:: https://codecov.io/gh/skypyproject/skypy/branch/master/graph/badge.svg
-    :target: https://codecov.io/gh/skypyproject/skypy
-    :alt: SkyPy's Coverage Status
-
-.. |PyPI Status| image:: https://img.shields.io/pypi/v/skypy.svg
+.. |PyPI| image:: https://img.shields.io/pypi/v/skypy?label=PyPI&logo=pypi
     :target: https://pypi.python.org/pypi/skypy
-    :alt: SkyPy's PyPI Status
 
-.. |Anaconda Status| image:: https://anaconda.org/conda-forge/skypy/badges/version.svg
+.. |conda-forge| image:: https://img.shields.io/conda/vn/conda-forge/skypy?logo=conda-forge
     :target: https://anaconda.org/conda-forge/skypy
-    :alt: SkyPy's Anaconda Status
 
-.. |Documentation Status| image:: https://readthedocs.org/projects/githubapps/badge/?version=latest
-    :target: https://skypy.readthedocs.io/en/latest/?badge=latest
-    :alt: Documentation Status
+.. |Read the Docs| image:: https://img.shields.io/readthedocs/skypy/stable?label=Docs&logo=read%20the%20docs
+    :target: https://skypy.readthedocs.io/en/stable
+
+.. |GitHub| image:: https://github.com/skypyproject/skypy/workflows/Tests/badge.svg
+    :target: https://github.com/skypyproject/skypy/actions
+
+.. |Codecov| image:: https://codecov.io/gh/skypyproject/skypy/branch/master/graph/badge.svg
+    :target: https://codecov.io/gh/skypyproject/skypy
+
+.. |Zenodo| image:: https://zenodo.org/badge/221432358.svg
+    :target: https://zenodo.org/badge/latestdoi/221432358
+    :alt: SkyPy Concept DOI