[NUCLEO_F030R8] Add SPI api, corrections in I2C
[NUCLEO_L152RE] Change SPI frequency setting
[NUCLEO_F030R8] Modify us_ticker to use only one timer
[NUCLEO_F030R8] Add pwmout api
Merge branch 'master' of https://github.com/mbedmicro/mbed
[NUCLEO_L152RE] Add PWM output, ticker with one timer

The us_ticker uses now only one timer instead of two. Another PWM output
on TIM4 has been added.
[NUCLEO_F103RB] Change ticker to use one timer...

and add another pwm output.
[NUCLEO_F103RB] Update to std periph driver V3.6.1
[NUCLEO_L152RE] Remove timer update interrupt in sleep

Otherwise the first update interruption will wake-up the MCU.
[NUCLEO_F030R8] Remove timer update interrupt in sleep
Typo corrections
Merge pull request #158 from bcostm/master

[NUCLEO_L152RE/F030_R8] SPI, I2C, Ticker, PWM updates