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

targets/TARGET_STM/PeripheralPins.h/shortlog@74e0ce7f98e8: not found in manifest