Radiation 2D - solves #289

adjust radiation kernel to work in 2D
solves #289 

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**Do not merge yet!**
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Currently, simulations are waiting on hypnos for verifying the physics/radiation results.  
If they produce correct results, this branch can be merged.
Up until then, feel free to comment on the code.
Thanks @PsychocoderHPC for the support on transferring the code to 2D.
an example: 
DataSpaceOperations<simDim>::map -> map a linear id in the space of the first parameter.
If superCellsCount is (4,4) and your super_cell_index is 6 the result is (1,1).
If you than add gardingSuperCells (=1) than you get (2,2) -> this is the right result.

In your case you add one to superCellsCount(4,4) -> (5,5) and map your linear index what result in (1,0).