[NUCLEO_F0] Add PeripheralPins files
[NUCLEO_F103RB] Add PeripheralPins files
[NUCLEO_F3] Add PeripheralPins files
[NUCLEO_F4] Add note on optional pins
[NUCLEO_L0/L1] Add PeripheralPins files
[NUCLEO_L053R8] Correct issue with Travis build
Merge pull request #738 from bcostm/master

Targets: NUCLEOs - Add PeripheralPins files for all nucleo targets