According to #3786 removed the reference to Leonardo only in while(!Serial) of the examples.
Changed in in "wait for serial port to connect. Needed for native USB port only"
correct SS pin setup is already handled by SPI subsystem.
this should prevent future issues like #2868
current implementation assures that:
* pin10 is OUTPUT HIGH if SPI.begin() is called and the pin was unconfigured
* pin10 state is not modified if pinMode(10, OUTPUT) is called before SPI.begin()
* pin10 is INPUT HI-Z if nor pinMode(10, OUTPUT) nor SPI.begin() are called
