Update XXX4000.py

Added _read_pcb_temperature based on the code originally from _read_temperatures in QR65000.py.  This has been tested on a USB4000 spectrometer.
Created colour.py as example of colour measurement

This script creates a live graphical interface to an OceanOptics spectrometer and calculates the CIE L*,a*,b* colour values for the current spectra relative to a set light source.  The file "CIE1931and1964.txt" must be in the directory where colour.py is executed.
Create CIE1931and1964.txt

This file contains the definition of the CIE1931 and CIE1964 colour response functions for human vision.
Corrected oversample_entry box

The oversampling entry box was setting the exposure time entry box.
Updated colour.py, correct buffering issues

Corrected buffering.
Added doc string to colour.py
Merge remote-tracking branch 'fluidhomefront/master'