Redesigned the DataFile class. UNTESTED
Re-design mostly done and working. Not fully tested, and mem-save option not done
FIXED: few bugs in addSignal for JSON models
Added merging of HDF5 files, and secting pulsars when reading HDF5 files
Working JSON models, with memory saving and accelerated preparations
In process of changing the signal class into a dictionary
Fully functional new JSON model implementation