Converts CONTRIBUTING.rst to actual reStructuredText rather than Markdown.

CONTRIBUTING.rst

@@ -1,4 +1,6 @@
-# How to contribute
+=================
+How to contribute
+=================
 
 Third-party patches are welcomed for improving Segpy. We simply can't
 access the huge variety of SEG Y files produced by a myriad of other
@@ -9,32 +11,36 @@ get things working in your environment, there are a few guidelines that we
 need contributors to follow so that we can have a chance of keeping on
 top of things.
 
-## Getting Started
+
+Getting Started
+===============
 
 The easiest way to help is by submitting issues reporting defects or
 requesting additional features.
 
-* Make sure you have a [GitHub account](https://github.com/signup/free)
+* Make sure you have a `GitHub account <https://github.com/signup/free>`_
 * Submit an issue, assuming one does not already exist.
   * Clearly describe the issue including steps to reproduce when it is a bug.
   * Make sure you mention the earliest version that you know has the issue.
 * Fork the repository on GitHub
 
-## Making Changes
+
+Making Changes
+==============
 
 * You must own the copyright to the patch you're submitting, and be in a
   position to transfer the copyright to Sixty North by agreeing to the either
-  the [Individual Contributor License Agreement](https://github.com/sixty-north/segpy/blob/master/docs/legal/segpy-individual-cla.pdf)
-  (for private individuals) or the [Entity Contributor License Agreement](https://github.com/sixty-north/segpy/blob/master/docs/legal/segpy-entity-cla.pdf)
+  the `Individual Contributor License Agreement <https://github.com/sixty-north/segpy/blob/master/docs/legal/segpy-individual-cla.pdf>`_
+  (for private individuals) or the `Entity Contributor License Agreement <https://github.com/sixty-north/segpy/blob/master/docs/legal/segpy-entity-cla.pdf>`_
   (for corporations or other organisations).
 * Make small commits in logical units.
-* Ensure your code is in the spirit of [PEP 8](https://www.python.org/dev/peps/pep-0008/),
+* Ensure your code is in the spirit of `PEP 8 <https://www.python.org/dev/peps/pep-0008/>`_,
   although we accept that much of what is in PEP 8 are guidelines
   rather than rules, so we value readability over strict compliance.
-* Check for unnecessary whitespace with `git diff --check` before committing.
-* Make sure your commit messages are in the proper format.
+* Check for unnecessary whitespace with ``git diff --check`` before committing.
+* Make sure your commit messages are in the proper format::
+
 
-````
     Issue #1234 - Make the example in CONTRIBUTING imperative and concrete
 
     Without this patch applied the example commit message in the CONTRIBUTING
@@ -46,21 +52,22 @@ requesting additional features.
     The first line is a real life imperative statement with an issue number
     from our issue tracker.  The body describes the behavior without the patch,
     why this is a problem, and how the patch fixes the problem when applied.
-````
+
 
 * Make sure you have added the necessary tests for your changes.
 * Run _all_ the tests to assure nothing else was accidentally broken.
 
-## Making Trivial Changes
+Making Trivial Changes
+======================
 
-### Documentation
+Documentation
+-------------
 
 For changes of a trivial nature to comments and documentation, it is not
 always necessary to create a new issue. In this case, it is appropriate
 to start the first line of a commit with 'Doc -' instead of an issue
-number.
+number::
 
-````
     Doc - Add documentation commit example to CONTRIBUTING
 
     There is no example for contributing a documentation commit
@@ -71,12 +78,12 @@ number.
     place of what would have been the ticket number in a
     non-documentation related commit. The body describes the nature of
     the new documentation or comments added.
-````
 
-## Submitting Changes
+Submitting Changes
+==================
 
-* Agree to the [Individual Contributor License Agreement](https://github.com/sixty-north/segpy/blob/master/docs/legal/segpy-individual-cla.pdf)
-  or the [Entity Contributor License Agreement](https://github.com/sixty-north/segpy/blob/master/docs/legal/segpy-entity-cla.pdf)
+* Agree to the `Individual Contributor License Agreement <https://github.com/sixty-north/segpy/blob/master/docs/legal/segpy-individual-cla.pdf>`_
+  or the `Entity Contributor License Agreement <https://github.com/sixty-north/segpy/blob/master/docs/legal/segpy-entity-cla.pdf>`_
   by attaching a copy of the current CLA to an email (so we know which
   version you're agreeing to). The body of the message should contain
   the text "I, <your name>, [representing <your company>] have read the
@@ -85,10 +92,11 @@ number.
 * Submit a pull request to the repository in the sixty-north organization.
 
 
-# Additional Resources
+Additional Resources
+====================
 
-* [Individual Contributor License Agreement](https://github.com/sixty-north/segpy/blob/master/docs/legal/segpy-individual-cla.pdf)
-* [Entity Contributor License Agreement](https://github.com/sixty-north/segpy/blob/master/docs/legal/segpy-entity-cla.pdf)
-* [PEP 8](https://www.python.org/dev/peps/pep-0008/)
-* [General GitHub documentation](http://help.github.com/)
-* [GitHub pull request documentation](http://help.github.com/send-pull-requests/)
+* `Individual Contributor License Agreement <https://github.com/sixty-north/segpy/blob/master/docs/legal/segpy-individual-cla.pdf>`_
+* `Entity Contributor License Agreement <https://github.com/sixty-north/segpy/blob/master/docs/legal/segpy-entity-cla.pdf>`_
+* `PEP 8 <https://www.python.org/dev/peps/pep-0008/>`_
+* `General GitHub documentation <http://help.github.com/>`_
+* `GitHub pull request documentation <http://help.github.com/send-pull-requests/>`_