* Implemented true 1:1 zoom and revisited zoom functionality
* Enabled direct loading of session file and loading last session   
* Implemented handling SOLARNET-standard tabulated FITS files
* Modified and optimised warping non-equidistant spectra
* Implemented per-diagnostic restriction of wavelength range
* Cosmetic changes to make control panel layout more compact 
* Fixed miscellaneous minor bugs (a.o., crashes on determining 
  scaling variables, negative indexing, WCS timestep selection)