* Set bootloader to stm32-dfu for STM32F303
* Set bootloader to stm32-dfu for STM32F0x2
* Set bootloader to stm32-dfu for STM32F4x1
* Set bootloader to stm32duino for sowbug
* Delete redundant bootloader_defs headers
* Add some missing MCU name comments
* Move APM32 dfu-suffix overrides underneath bootloader
* Remove redundant STM32_BOOTLOADER_ADDRESS defines/rules