[GRASS5] New CSS based doc style for GRASS usage examples

[Markus Neteler]

Hi all,

- documentation cosmetics -

I have extended:
 lib/gis/parser.c
 include/Make/Html.make (separated from Rules.html)
 tools/build_html_index.sh

to generate an additional HTML header line to include a simple
CSS style file. Basically the examples can be coded now
like this in the 'description.html' files:

<div class="code"><pre>
v.to.db -p roads option=length type=line units=k
</pre></div>

Such an example appears indented with type write font in a grey box
which makes it easier to distinguish in the text flow.
And: Section titles are green colored now (such as the GRASS Web site).

Example:
 vector/v.to.db/description.html

TODO 1:
Now all the tons of examples should be homogenized and changed to
above style.

TODO 2: Fix tools/g.html2man/g.html2man to accept multiple lines
in above environment (two or more lines of example in a single

<div class="code"><pre>
...
...
</pre></div>

At time the line break is eaten and not preserved (hi Daniel, maybe
you could help?). Maybe these examples could be indented a bit in the
MAN pages?

By tomorrow morning Italian time the updated man pages will be online.

Markus