add window function hpp file

add file to include different window function
    still empty
add box and triangle window function
correct naming of filters
add default setup for radiation filters
add radiation window filter calls to radiation plug-in
adjust example radiiationConfig.param files

adjust example radiiationConfig.param files to include
       new filter setup
correct errors in code
fix wrong encapsulation of namespaces
correct call of global grid in kernel
fix simBox size

fix windowFunction parameters
    previously sim size in number of cells
    but real size needed
correct typos
convert class to struct

convert class to struct
remove empty constructure
remove public and private
correct typos
remove remarke on more memory usage
change precompiler flag
remove and add whitespaces
simplify window function
make window 2D compatible

make window function call 2D compatible
add improvements with DataSpace<simDim>
revert premature 2D implementation
update changelog