Add TCA9548A Multiplexer Support

• Add support for TCA9548A I2C Multiplexer. Tested with https://www.adafruit.com/products/2717 breakout. (johnbryanmoore)
• Add python example using TCA9548A Multiplexer support (johnbryanmoore)

Simplified build

1. Simplified build process (svanimisetti)
2. Added python example that graphs the sensor output (svanimisetti)
3. Updated the build instructions (svanimisetti, johnbryanmoore)

Add Multiple sensor support

1. Add multiple sensor support
2. Add additional error checking

Initial "Beta" Version

Initial beta version. Supports only 1 device and limited error checking.