Adds support for rendering handlebars templates

- Includes the handlebars runtime
- Includes a grunt handlebars task
- Leverages handlebars to render the footer (src/template/footer.hbs) in
every slide
Allows README.md to have a Windows line-ending

- Before, the slide separator was '^\n---\n', which would not work if
the README.md file had Windows line-ending.
- Now, the slide separator is '^\r?\n---\r?\n', which matches Unix and
Windows line-endings.
Starts the config for the talk-es6
Revert "Starts the config for the talk-es6"

This reverts commit 91d4086f526da84e974da665b26ad8658ecdeb35.