merge postmessage api

fix vertical transition for vertically centered slides, vertical centering is now on by default (#70)

update syntax highlight after editing (#210), move markdown and highlight scripts from lib to plugin

Using the latest Uglify JS with --no-seqs and deleting 'use strict' statement for use in production.

Conflicts:
	js/reveal.min.js

Need to generate a new minified version afterwards.

Its was impossible (at least for me) to keep the windows in sync without bloating the code too much.

Using the latest Uglify JS with --no-seqs and deleting 'use strict' statement for use in production.