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The HTML top section is expected to be reused in various templates that
are going to be created. To allow reuse, the top HTML part is extracted
from the default template into the includes directory.

The new baseline for the paddings are
  * 16rem top
  * 10rem bottom
Tablet-sized displays scale the padding to 0.75*baseline,
phone-sized displays to 0.5*baseline.

Since this may be repeated once different layouts are created, and the
default layout got quite convoluted, the title image section was put
into its own file.

The image is determined by the "title-image" option in the
front-matter of the markdown file. It can either be the keyword
"default" or the name of an image file. The image file is expected
to be found in the image directory (c.f. _config.yml).
Should the option be unset or the image not be found the blue
background color as set in title-image.css will be used instead.

To achieve this, the file "_config.yml" has introduced which holds basic
configuration which applies to the whole site as to avoid magic strings.

Noticed some left-overs from the original design that were
commented out and partially not transferred over yet.
It is done now.

As a result the title image will now take up a lot less space
when displayed on a small screen.

(Issue #4)

This commit creates a basic Jekyll setup for a HIFIS website.
It already contains an adapted corporate design and all required
assets.

Support for small screen devices is included, although the
breakpoints are just taken over from the CD even if they seem
rather arbitrary.

The required javascript has been inlined since it boiled down to
half a line of code at one specific place. (c.f. the <button> in
_includes/header.html)

As a basic concept, most sites are supposed to be written in
Markdown, using HTML for enrichment. Pure HTML-only sites are
supported.

Known issue: Many linked sites are still missing including
	* Team
	* Imprint
	* Privacy
	* Contact
These should be added by future commits.