Document generator

requires doxygen.

Initial attempt on generating documentation for OmegaWiki developers.

Patch 2: removed trailing and improve upon the OmegaWiki.md

Patch 3: moved the codes to the doxygen folder. Moved the md files to the
WikiLexicalData root directory.  I kind of dislike the class generated
from directory showing the directory from the root directory.

md files are now side by side with the README and other important notice,
which will be updated when the md files are up-to-date.

Kip, if you think md files should be placed on the doxygen folder, inform
me, I will move them, if you feel it is better.

Pathc 4: forgot to remove deleted files. deleted.

Change-Id: If90c17aece79f88199e9f175419bd754ed95949e
Merge "Document generator"