Put in some debug code
Display filename and add lineprofile function
Convert all display stuff to functions

This makes for much easier handling and re-use of the code.
I *need* to get the hang of this :)
Nicely display the line profile in a final plot

- The final plot from DisplayExperiments is now usable, i.e. we see both
  original images on the top left, the corrected on the top right and
  the line profile (manually selected) on the bottom
- The line profile function is now globally usable, we probably should
  switch to it with AnalyzeGrid.py...
- The line profiler generates both the interpolated and nearest
  neighbour line profiles and displays them nicely.
  The function returns the start/end points in image coordinates and the
  interpolated line profile
- PyCharm finds *no* `pep8` errors anymore