mbed library sources. Supersedes mbed-src. Fixed broken STM32F1xx RTC on rtc_api.c

Dependents:   Nucleo_F103RB_RTC_battery_bkup_pwr_off_okay

Fork of mbed-dev by mbed official

drivers/I2C.h/shortlog/shortlog@b96e65c34a4d: not found in manifest