fixed issue in vtu-reader where declared precision of node coordinates was smaller than actual precision
delete LinAlg/SystemOfLinearEquations dir and make LinAlg/Lis dir
add LisCheck.h
add LisVector
add LisMatrix
add LisTools
add LisLinearSolver
change LisLinearSolver constructor as it takes LisMatrix and option as arguments
remove unnecessary log output
add is_assembled variable in LisMatrix because lis_matrix_is_assembled() is not working.
Changes to cleanup class LisMatrix.

- Reformatted code
- Made docu more meaningful
- Changed name of first parameter of constructor
- Moved implementation of setValue() and getValue() from header into cpp-file
Some code cleanup in LisLinearSolver.
Changed the implementation of LisMatrix::getMaxDiagCoeff().

- Removed the update code for calculation of _max_diag_coeff from
  + LisMatrix::setValue()
  + LisMatrix::addValue().
- Removed the _max_diag_coeff attribute.
- Implemented the functionality in LisMatrix::getMaxDiagCoeff().
Added parameter for penalty to applyKnownSolution(), some formatting.
Move up using boost ptree directive.
Qualify const LisMatrix class attributes.
Comment LisMatrix class attributes 'is' and 'ie'.
Reset _is_assembled flag on modifications.
Correct lis vector row access in getMaxDiagCoeff().
Qualify const LisVector class attributes.