Due to the way the headers are organized changing a single change in
an AP_Notify driver would trigger a rebuild for most of the files in
the project. Time could be saved by using ccache (since most of the
things didn't change) but we can do better, i.e. re-organize the headers
so we don't have to re-build everything.
this changes AP_Notify to use updates via notify.update() at 50Hz,
avoiding the need for the 1kHz timer. It also creates a parent class
for ToshibaLED so that the I2C and PX4 ToshibaLED drivers can be
abstracted out.
Pair-Programmed-With: Randy Mackay <rmackay9@yahoo.com>