Rename docs/*.md => docs/*.txt

The documentation uses features of Python-Markdown that are not supported on
GitHub and it's better to get a source view of the docs anyway. For example,
that way comments and bug reports can reference a specific line of a file.

Of course, it makes sense for Github to render the README, so that is left
with the `.md` file extension.

1 files changed, 69 insertions, 0 deletions

diff --git a/docs/extensions/fenced_code_blocks.txt b/docs/extensions/fenced_code_blocks.txt
new file mode 100644
index 0000000..0aa0d34
--- /dev/null
+++ b/docs/extensions/fenced_code_blocks.txt
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+title:      Fenced Code Block Extension
+prev_title: Definition List Extension
+prev_url:   definition_lists.html
+next_title: Footnotes Extension
+next_url:   footnotes.html
+
+Fenced Code Blocks
+==================
+
+Summary
+-------
+
+This extension adds a secondary way to define code blocks which overcomes a few
+limitations of the indented code blocks.
+
+This extension is included in the standard Markdown library.
+
+Syntax
+------
+
+Fenced Code Blocks are defined using the syntax established in 
+[PHP Markdown Extra][php].
+
+[php]: http://www.michelf.com/projects/php-markdown/extra/#fenced-code-blocks
+
+Thus, the following text (taken from the above referenced PHP documentation):
+
+    This is a paragraph introducing:
+
+    ~~~~~~~~~~~~~~~~~~~~
+    a one-line code block
+    ~~~~~~~~~~~~~~~~~~~~
+
+Fenced code blocks can have a blank line as the first  and/or last line of a 
+code block and they can also come immediately after a list item without becoming
+part of the list.
+
+In addition to PHP Extra's syntax, you can define the language of the code 
+block for use by syntax highlighters etc. The language will be assigned as a 
+class attribute of the ``<code>`` element in the output. Therefore, you should 
+define the language as you would a css class - ``.language``. For consistency 
+with other markdown syntax, the language can *optionally* be wrapped in curly 
+brackets:
+
+    ~~~~{.python}
+    # python code
+    ~~~~
+
+    ~~~~.html
+    <p>HTML Document</p>
+    ~~~~
+
+The above will output:
+
+    <pre><code class="python"># python code
+    </code></pre>
+    
+    <pre><code class="html">&lt;p&gt;HTML Document&lt;/p&gt;
+    </code></pre>
+
+Usage
+-----
+
+From the Python interpreter:
+
+    >>> html = markdown.markdown(text, ['fenced_code'])
+
+
+