by default false. if true overwrite existing group

also some cosmetic cleaning

if you have templates head.tmp, queue.tmp in
running directory then these are used instead..

starts ht condor run

can now save toutatis files correctly

toutatis distributions has a 7th line of zeros
now can read both correctly

if merging files with differing length of arrays, assume
that the shorter one lost all beam

close buffer in case trying to save file multiple times..

new function which saves the density data into a HDF5 file format
useful after e.g. combining multiple data..

seems number of header lines vary..