ADC Conversion Time Comparison: Arduino Uno, Teensy 2.0, Teensy LC, Teensy 3.1

Comparison of analog conversion times (plus a bit of int swapping / checking) for:
• Arduino Uno (112 microseconds)
• Teensy 2.0 (60 microseconds)
• Teensy LC (16 microseconds)
• Teensy 3.1 (10 microseconds)