read me updated
fixed return type
display functions restructured, new symbols

function only for the symbols added, all other files updated with new
function
little correction of display symbol constant

there was a mistake in the description of the character S.
added the new states, function will follow
added another state for initialization of carriage

changes for new Slider::setParameters
experiments for driving stepper

commit before changing to new branch, because it´s not working now.