SONATA reports support (BlueBrain#11)

* Remove the offset from the mapping
 - Order it by cellIndex first and SectionId second
 - Ensures the same results for both binary and SONATA reports

readme: submodules are no more (BlueBrain#5)

* submodules are no more
* another typo bytes the dust

Update to brion 3.3.1 (BlueBrain#3)

* Use plain CMake (remove common/CMake dependency)
* remove submodules
* emSim 1.0.1