Merge branch 'master' of https://github.com/mbedmicro/mbed
[STM32F0] Add TARGET_STM32F0 folder

With STM32Cube inside.
[NUCLEO_F030R8] Move files in STM32F0 folder
[NUCLEO_F072RB] Move files in STM32F0 folder
[NUCLEO_F091RC] Move files in STM32F0 folder
[NUCLEO_F030R8] Remove old folder
[NUCLEO_F072RB] Remove old folder
[NUCLEO_F091RC] Remove old folder
[NUCLEO_F072RB] Update gpio/port structures

Needed due to the new STM32Cube version used.
Merge pull request #660 from bcostm/master

Targets: STM32F0 - Factorisation of NUCLEO_F030R8/F072RB/F091RC cmsis folders