Readme sections edited, cleaned up code

For Owen's functions, separated the long equations into blocks by using
... (ellipses)
For Malte's function, changed the name of t_lenth (this was a typo) and
t_length into timeLength
For GUIScript:
-> Thanks Will for buttons, looks great, will take it on board and
reposition it later
-> global variables used but can we avoid this somehow? tried Malte's
suggestion to callback all the inputs from GUI into a separate function
for return back to script but variables are not returned to the
GUIScript properly.