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When generating the documentation via 'make doc' the HTML version of the Ada
source code is generated, too. 'pygmentize' is used therefor. Indeed, it has
some bugs:

1.) Raising exceptions with directly passed error detail messages aren't
    highlighted correctly, they're treated as corrupted strings till the
    very last end string quotation mark in the source code file.
        raise Error with "Description";

2.) Range definitions are highlighted as broken floating point numbers.
        for I in 1..2 loop

Therefore I generated the HTML version with Kile.

Also improved reStructured Text file with some formattings and hyperlinks,
so it's better readable as HTML version. Introduced some meta data as well
as corrected some small mistakes.

Updated Makefile and .gitignore to new HTML readme.