cpu - stm32f4: add support for stm32f415rg
cpu - stm32f4: added support for more channels/devices in periph impls
board - msbiot: initial import for the msbiot
tests/examples: blacklisted msbiot for some tests
licenses: added stm specific 3 clause BSD license pattern
Merge pull request #1494 from fnack/msbiot_reworked

Initial import of MSB-IoT board