Changed the behavior of the HomeoUnit input unit. Instead of always scaling
the value read from the sensor and centering it at 0 (thus allowing for both
positive and negative values), the default behavior is now to scale the value
read from the sensor to the range 0-MaxDev, hence always positive.

The value centered at zero can still be obtained by setting the unit's ivar
always_pos to FALSE

 Changes to be committed:
	modified:   src/RobotSimulator/HomeoUnitNewtonianTransduc.py
Completely rewrote first two sections of research notes on Robotic Experiments
(type-1 Braitenberg-like vehicles with no-self connections and M-->M self-connection).
Also, carried out relative experiments, and inserted illustrative data in the document.

	modified:   Research-notes/Homeo-Robotic-Experiments-and-Expected-Results.lyx
	new file:   Research-notes/Images/Braiten-1-gradient-2.pdf
	new file:   Research-notes/Images/Braiten-1-gradient-2.svg
	new file:   Research-notes/Images/Braiten-1-gradient-3.pdf
	new file:   Research-notes/Images/Braiten-1-gradient-3.svg
	new file:   Research-notes/Images/Braiten1-Newtonian-damped.EPS
	new file:   Research-notes/Images/Braiten1-Newtonian-undamped-2.EPS
	new file:   Research-notes/Images/Braiten1-Newtonian-undamped.EPS
	new file:   Research-notes/Images/Braiten1-world-2.png
	new file:   Research-notes/Images/Braiten1-world.png
	new file:   Research-notes/Images/Braiten2-world-webots.png
Minor modification to a function in Helper functions (made sure that scaling
of value produces float valules), and minor edits to the experimental setup
for Braiten-like type 1 vehicle experiments.

 Changes to be committed:
	modified:   src/Helpers/General_Helper_Functions.py
	modified:   src/RobotSimulator/HomeoUnitNewtonianTransduc.py
	modified:   src/Simulator/HomeoExperiments.py