Version 2.4

Removed RGB LED code to tailor it to the PCB (Rev 1.0). Interrupts
temporarily disabled until buttons connected, otherwise they are
constantly triggered (slowing it down so it's unusable).
Version 3.0

Rewrote code to be used with the Teensy 3.1 board and utilizing its
built-in capacitive sensing. Faster SPI speed (12MHz) greatly improves
the loop rate. Now runs at about 97 ms/loop with the screen active and 3
electrode (96Mhz clock).  If overclocked to 120Mhz, 82ms/loop.
Version 3.1

Added option to log electrode position (for experiments) and change the
position via buttons. Eliminated raw data from the display and replaced
with more capacitance readings. Consolidated the display code to a for()
loop and set to only display every X loops while data logging. Added
flush() command to save logged data every 100 samples. This prevents
data loss if power is lost during data logging.
Version 3.2

Increased number of electrodes being monitored to 9. Various
optimizations for increased display speed; 200ms with 9 values being
updated
Version 3.3

Switched to optimized library for ILI9341 (which also works for ILI9340)
from PJRC. Screen refresh rate is now 12.5ms!! No longer suppressing
screen update while logging data. Add bar graphs to the right of each
value. This increased the refresh rate to 25-30ms (depending on values).
However, if overclocked to 120Mhz it drops to 20-25ms. Had to remove the
cochlea bitmap to make room for the graphs.
Version 3.4

Moving to battery powered handheld device.  NOTE: in order to program
via USB, the power button must be in the 'on' position! I believe this
is due to the ground wire of the switch being connected when the switch
is 'off'. Added analog input to monitor battery voltage. Using correct
values of resistors in the voltage divider gives a value about 9mV
higher than battery voltage. Added biasing button. If bias performed
before logging is started, bias values are stored as first line in the
csv file. Otherwise, it will be evident in the file because all values
will simultaneously go to zero (and the bias values will be the average
of the previous 100 samples). Added restart button. Updated the
ILI9341_t3 library that included a fix for the omitting of the bottom
part of characters such as g and y.
Version 3.5-untested

Replaced manual position logging with automatic via my custom Digimatic
library. This will allow Mitutoyo calipers to be connected for real time
measurement logging. This is only done every couple loops though because
each measurement takes ~35ms. Added a delay (10 samples) before
beginning biasing to allow finger to be removed (touching the case
affects the measurements slightly)