\cond 0 -> \cond SKIP_THIS

as '0' is not a valid doxygen section label.
changed \text{grad} to \textbf{grad} in docu

Dumux-Svn-Revison: 10355
Ported-By: Andreas Lauser <andreas.lauser@iws.uni-stuttgart.de>
replace remaining \text{grad} by \textbf{grad}
removed <tt> for the sake of the handbook change \textbf{div} to \text{div}

Dumux-Svn-Revison: 10358
Ported-By: Andreas Lauser <andreas.lauser@iws.uni-stuttgart.de>
subsitute last \textbf{div} by \text{\div}
Bugfix: wrote out of bounds. It took gcc 4.8 and -O2 -g to trigger a segfault that could be tracked down by valgrind. Approved by Thomas.

Dumux-Svn-Revison: 10359
Ported-By: Andreas Lauser <andreas.lauser@iws.uni-stuttgart.de>