[Dfu-util] call for testing: dfu-util 0.10 RC

Hi, I consider the current git head to be a release candidate for the upcoming 0.10 release of dfu-util, so I would be glad to see some testing on various devices. I have tested on STM32F4 and will test some custom IAP bootloaders. There are still known issues on STM32L4 and STMF0, but that has to wait for later releases. Thanks, Tormod