updated the project build configs to include the SpikePlot.cpp and .h files and exclude the previous plotters

Signal Generator now generates fake action potentials!!! The phase dial can be used to scale up and down noise on the spikes

initial commit of SpikePlot.cpp and SpikePlot.h which define a general spike plotting object that can completely replace ElectrodePlot, TetrodePlot, StereotrodePlot. SpikePlot objects can be added to the canvas and render fine, however, eventually the Tetrode variant of the SpikePlot causes a segfault, probably due to the way that spikes are copied around in the SpikeDisplayCanvas.

The IntanThread can report TTL events on its 6 input channels. This was tested
with an Arduino; input detection is fast and reliable.

The IntanThread also generates its own timestamps, allowing the software to move
toward a framework in which timestamps come from input sources, rather than
from the RecordNode.

Finally, an ArduinoOutput module was added, which allows the software to
communicate with an Arduino via serial output.

This appears to be the source of the inconsistencies, at least on OS X.