Implemented a more pleasant HTML template for notes.
Ensured that Git ignores the .DS_Store artifact on Mac OS X.
Ensured that `rst2html` generates sections as <h2> tags, not <h1>.

See: http://docutils.sourceforge.net/FAQ.html#unexpected-results-from-tools-rst2html-py-h1-h1-instead-of-h1-h2-why
Implemented a customized `rst2html.py` script for note rendering.
Customized <blockquote> footer rendering for Bootstrap.

See: http://getbootstrap.com/css/#type-blockquotes
Customized admonition rendering for Bootstrap.

See: http://getbootstrap.com/components/#alerts
Added a mention of `apt-get clean` to the Ubuntu notes.
Added a note regarding OCaml installation with MacPorts.
Added placeholders for notes to come.