Port of the TMP006 example code to python, some fixes for 16bit SPI access from python

I've ported the TMP006 example from c++ to python.  It seems to work for me, hopefully it will be useful to someone else too.

I hereby assign any rights I may have had to this code to Adafruit (though I doubt I had any, since most of the code is copied from y'alls' original driver.)

I had some trouble with the Adafruit_I2C.py i2c wrapper when doing 16-bit accesses using the 8-bit approximation that was in the old code -- the TMP006 didn't like that -- so had to "fix" how those were done.  I've also tested those "fixes" with the BMP085 driver and it works, but since I don't have any of the other hardware, can't verify that they're working with the new 16-bit access functions.

Cheers, mt