Start electron creation debugging

The code compiles but deadlocks the nodes, so let's do much out-commenting
and printing.
Creating electrons works - unsure about the number

Several corrections have been made so that now the creation of electrons
works. Still there seems to be a greater amount of electrons in the end
than should be possible with only 1 ionization per macro-ion.

Changes:
 -- correct position of infinite loop (after ionization)
 -- remove on if-statement because of redundance
 -- remove (0 <= electronId < particlesInSuperCell) and replace with valid exp.
 -- rename particlesInSuperCell with maxParticlesInFrame
 -- set maxParticlesInFrame as SuperCellSize::elements
 -- add electrons->fillAllGaps because that was missing
 -- change order of cloning (now 1) and setting momentum (now 2)
 -- move "isParticle" definition into loop over frames