Fixes #511. Thanks to @omiday for the report.

The documentation is not accurate when lazy_ol=False parameter is called.

The example shows the 'start' attribute to the first <li> tag. However, the attribute is in the <ol> tag:
>>> import markdown
>>> s = """
... 4. Apples
... 5. Oranges
... 6. Pears"""
>>> markdown.markdown(s, lazy_ol=False)
u'<ol start="4">\n<li>Apples</li>\n<li>Oranges</li>\n<li>Pears</li>\n</ol>'


The behaviour of the library is the correct one (https://developer.mozilla.org/fr/docs/Web/HTML/Element/ol), so the documentation need to be fixed, not the library.

Both `safe_mode` and `html_replacement_test` keywords are
pending deprecation, as are positional args. Closes #337.

The builtin extensions will no longer get special treatment and have
the path ("markdown.extensions.") appended . The same applies for
"mdx_" extensions. All names extension must provide the full path.
Fixes #336.

Also deprecating support for passing in extension config settings
as part of the string name. The extension_configs keyword should
be used instead. Fixes #335.

Also raising PendingDeprecationWarnings for positional args or the
"config" keyword on the Extension Class. Pass each setting as a
seperate keyword instead.

Docs and tests are updated. Still need to update extension API docs.

Noted that using keywords it the prefered method of passing config options to extensions. Also updated the example sto demonstrate the new prefered way as discussed in #325.

This is related to waylan/Python-Markdown#305.