WIP - Teensy 3.1 support

This is a WIP - Adding support for Teensy 3.1.  If possible it will use
the Teensy using very fast hardware SPI support mode.  Currently have
optional parameter on constructor that forces it to use slower SPI.

There is issue with displays with setups like the 2.8" TFT with touch,
where fast SPI will not work with touch screen code.  Have hack in place
in test program to swap.

Again WIP WIP WIP!!!