[NUCLEO_F302R8] Migration to STM32Cube driver.

Actual code is based on the Standard Peripherals Library.
[NUCLEO_F302R8] Remove stdlib folders

Not used, was there as backup.
[NUCLEO_F302R8] Fix bug with MBED_A7 test (irq edges disabled)
Merge branch 'master' of https://github.com/mbedmicro/mbed
[NUCLEO_F302R8] Fix issue with MBED_A7 test

Add new STM_MODE_IT_EVT_RESET GPIO mode.
Merge branch 'master' of https://github.com/mbedmicro/mbed
Merge pull request #496 from bcostm/master

[NUCLEO_F302R8] Migration to STM32Cube driver.