removes LICENSE ficle
Squashed 'stm32f4_discovery_usb_cdc/' content from commit 7f565a4

git-subtree-dir: stm32f4_discovery_usb_cdc
git-subtree-split: 7f565a4b02d2adb3d05d05055fad6f0b4c899bf2
Merge commit '9629cea31879297ec1d1c792456fe9d02122f7f9' as 'stm32f4_discovery_usb_cdc'