[NUCLEO_F030R8] Add I2C master api
[NUCLEO_F103RB] Minor corrections on I2C master api
[NUCLEO_L152RE] Add SPI api
[NUCLEO_F103RB] Correction on I2C gpio configuration
[NUCLEO_L152RE] Correction on I2C gpio configuration + code cleanup
[NUCLEO_L152RE] Update std periph driver to V1.3.0
[NUCLEO_F030R8] Change AF setting before GPIO setting
[NUCLEO_F103RB] Change AF setting before GPIO setting
[NUCLEO_L152RE] Change AF setting before GPIO setting
[NUCLEO_L152RE] Add sleep api
Merge pull request #154 from bcostm/master

Update of I2C, SPI, SLEEP for NUCLEO_F103RB and L152RE