Updates to dependencies / serial port updates

[Hecatron]

• Updated the dependencies as much as possible without breaking continuous integration scripts
• allow the use of the newer versions of usbd-serial and usb-device
  and fix this issue Compatibility with usbd-serial 0.2.0 and above / usb-device 0.3.0 and above #213
• Updated the examples for the usb serial port
• Updated the examples for the latest cortex-m-semihosting

All that should be left now is

• embedded-hal 0.2.7 -> 1.0.0
• examples that use embedded-graphics 0.6.2 -> 0.8.1

[eldruin]

Great, thank you!
Could you add an entry to the changelog about the update to the dependencies?

[Hecatron]

ok all done

[eldruin]

Thank you!

[eldruin]

For the record, I have published this in version 0.8.0