Set horizontal margins

Set the horizontal margins to be 3mm.

Read:

- http://wiki.contextgarden.net/Layout
- http://context.aanhet.net/svn/contextman/context-reference/en/co-pagedesign.pdf

for more details on the layout.
Set vertical margin

Set the top margin to be 2mm and the bottom margin to be 1mm.

Disable headers, but keep some small space for footers (to show page number
etc. in a smaller font size).
Remove layout visualization

Now that the margins are set, remove layout visualization.
Change fonts

Latin Modern, the default ConTeXt font, does not look good in presentations.
Use the `simplefonts` module to change fonts easily. First we load the module,
and set the font size to 12pt (personal preference).
Use prefered font setup

The `simplefonts` module makes it easy to choose a font setup. I use:

- Fontin as main font
- Delicious as Sans font (for headings etc)
- Dejavu Mono Sans as Monoface font
- Neo Euler as math font