Added delay afer reset

As described in the datasheet the reset of the RF12 module can take
up to 100ms. This commit adds a delay of 100ms after reseting the
device.
Issue #11 Solving timing issue on CS line

This commit adds a delay of 1 microsecond between sending a spi
command and setting the cs line back to HIGH state.
Fix typing error in RF12_T3.h

There was a typing error. Fix it.
minor changes to get RFM12BP working with Teensy 3.1