Set document metadata

Simply set the metadata. The next few commits will show how to use this
metadata.
Add metadata to footer

Again, this is a matter of personal choice. I like to include the presentation
title and the author in the footer of each slide. Read:

- http://wiki.contextgarden.net/Headers_and_Footers

for details on setting the footer and

- http://wiki.contextgarden.net/Inside_ConTeXt#Using_variables

for information on variables.
Simple title page

This shows how to create a titlepage. The main idea is to use the `set` key for
variables to call a setup that uses a `makeup` page to create the titlepage.
Notice that the page numbers of the subsequent pages are correct. This is
because we used `\userpage` and `\lastuserpage` to show page numbers, and a
makeup page does not increment the userpage number.

The title page is has no style setup. The next few commits will show how to add
different style elements to the titlepage.
Added styling to titlepage

There are different ways to add style to the titlepage. I create different
style commands: `titlestyle`, `authorstyle`, etc for each metadata element and
then use them to style the corresponding element.
Sample text for display math

Notice that by default, ConTeXt uses `\blank[big]` around displaymath. In the
next commit, In the next commit, I will correct the spacing.
Set spacing around display math

Setting spacing around display math is a bit tricky. The obvious

    \setupformulas[spacebefore=small, spaceafter=small]

does not work. I think that this is because I use

    \setupwhitespace[big]

and ConTeXt vertical spacing model is such that the largest vspace value (big
in this case) wins.

After a bit of trial and error, I settled on this:

    \setupformula
        [spacebefore={nowhite,quarterline}, spaceafter={back,nowhite,quarterline}]

For `spacebefore`, the parameter `nowhite` kills all the whitespace and
then `quarterline` sets the space before the formula to be 0.25\lineheight.

Surprisingly, the same setting `{nowhite,quarterline}` does not work when used
for `spaceafter`. We need an addition `back` parameter to kill the previous
vpsace.
Example text for images

The simpleslides module provides two ways of including images: a horizontal
mode and a vertical mode. I like that, and want to provide similar alternatives
in this case.

A horizontal image should occupy as must horizontal space as possible without
overflowing the page height.

A vertical image should not be wider than 0.5\textwidth and should occupy as
much vertical space as possible.

For now, we use dummy settings `horizontal` and `vertical` for these two types
of images. The actual settings will be defined in the the next commits.
Remove figure numbers

I don't prefer the figures in presentations to be numbered so I remove them.
Define settings for horizontal images

Read:

- http://wiki.contextgarden.net/Command/defineexternalfigure

for details on defining settings for figures.

To determine the amount of vertical space left on the page, we define a measure
`page`. The exact value of this measure is taken from a solution by Wolfgang
Schuster on the ConTeXt mailing list.
Add setting for vertical images

The idea for the settings for vertical images is the same as that of horizontal
images. We add a little bit more vertical space around vertical images.
Tweak space around figures

By default, ConTeXt includes a big space before and after a float. I find that
to be excessive; so I reduced the space.

See:

- http://wiki.contextgarden.net/Command/setupfloat

for details.
Prelim to defining a fancy background

I want to add some subtle affects to the background. For that, I will use
MetaPost. As a first step, I redraw the colored background using MetaPost. See
the MetaFun manual for details.
Create a subtle red border around each slide

I like this subtle background, but this example shows that you are free to pick
any MetaPost graphic that you like as a background.
Add a visual counter for page numbers

See the documentation of t-visualcounter for details.

- http://modules.contextgarden.net/dl/t-visualcounter/doc/context/third/visualcounter/visualcounter.pdf