Support presenter notes

Allow slides using the "note" directive to contain
presenter notes that are displayed only in the presenter
console.

Change-Id: I9230e7a72f39400aa5b02e76c16da0338ca764b5
Signed-off-by: Doug Hellmann <doug.hellmann@gmail.com>
Merge pull request #29 from dhellmann/presenter-notes

Support presenter notes
Added presenter notes to the changelog.
Use display:none on notes, to prevent them from taking up space.
Updated presenter notes to handling to only collect note admonitions
Added presenter notes to the smoketest document.
Ignore lib, include, etc
Defer loading JS until the end of the document.
Support custom Javascript in slide themes.
Fire a Javascripte event on slide resizing.
Added support for specifying slide_classes in slide_conf
Copying build, figure docs into styling so all visual stuff is in one place.
Added fade-in, appear transition classes.
Added hieroglyph-quickstart program for bootstrapping presentations.
Sphinx test and test loading infrastructure.
Adding initial unit tests for slideconf directive.
Fixed bug when content is included when autoslides are disabled
Fixed issue #30: slides directive may omit title or content.
Fixed issue #26: slide numbering is just plain wrong.

Previously we were incrementing the slide count:

a) as soon as we visited a slide, and
b) regardless of whether or not this slide was going to be rendered as
   a slide or a div.

After incrementing, however, we'd often call depart_slide to close the
previous slide. To compensate for (a), _add_slide_number was called
with (count - 1) when departing a slide.

This commit simplifies the logic: we increment right before we call
starttag, and only when we're creating a slide. This means we also
don't need to worry about subtracting 1 to get the actual slide
number.
Adding Travis CI configuration.