add markdown functions and css
add (markdown) docs to master menu / nav bar
comment out some dead code for clarity
pass page active status to admin (for CRUD)
markdown: recognise new markdown category type

controller_page recognises new category type 'markdown'. Sets a flag to
instruct master template to load markdown.css (in all cases)
TODO: amend the markdown.css to affect markdown content class elements
only, rather than conflicting with main site css for elements h1...6 etc
If rendering a markdown page, pass the marked up html in md_content -
otherwise pass rawcontent (raw markdown to admin, or plain content
untouched)
markdown: controller_api_page

added markdown filter functions to page API
made the page API's GET method smart enough to know when to return just
raw content, or both raw markdown and html markdown content.
Returns md_render flag with content and lets the caller decide which
version in needs to render.
markdown: modified template set

Adding a clone of the basic template set, have stripped out the site
logo and banner image, and added very simple support for markdown
* added menu item to master.php
* altered default.php so that a truncated preview of the (raw) markdown
is shown on the markdown category page (indicated by slug='md' - see the
SQL provided below), with a permalink to view the full html version

-- in these examples, my site id is 3 and the category id is 2. adjust
to suit

-- strip the id out of this query, but find the inserted id after
running this:
INSERT INTO `category` (`id`, `title`, `slug`) VALUES (2, 'Markdown',
'md');

-- now change "2, NULL, 3, NULL, 'N', 1);" to "<YOURCATIDABOVE>, NULL,
<YOURSITEID>, NULL, 'N', 1);" and note the new column 'active'=1 on the
end.
INSERT INTO `pages` (`title`, `content`, `slug`, `category_id`,
`special`, `site_id`, `template`, `protected`, `active`) VALUES
('markdown2', '## Creating a RESTful API with Silex using Composer and
PHPUnit\n\nRecently I\'ve been playing around with Silex largely due to
wanting to experiment with the various frameworks out there but also
because I wanted to have a play around with composer. ... snip...
\n\nI\'ve not put all the tests in the tutorial - but you can find them
in the repo on GitHub (<http://github.com>)\n', 'markdown2', 2, NULL, 3,
NULL, 'N', 1);

-- category is null (its a category page) but change site id from 3 to
suit
INSERT INTO `pages` (`title`, `content`, `slug`, `category_id`,
`special`, `site_id`, `template`, `protected`, `active`) VALUES
('Documents', 'Please choose a document to view by clicking it the
title. The markdown will be converted to HTML!', 'md', NULL,
'a:1:{s:8:"category";s:8:"markdown";}', 3, NULL, 'N', 1);