Merge branch 'bug-12084-fix-gcc-4-1-errors-because-of-warnings'

• bug-12084-fix-gcc-4-1-errors-because-of-warnings: Use the proper types for level and window variables. Removed itkTypeMacro to get rid of unneeded virtual function. Use cmath for overloaded std::abs function prototypes Fixed warnings with gcc 4.1.2 which are treated as errors.