Device management fx subcommands

Command Description
aemu DEPRECATED! deprecated: alias for fx emu
cp copy a file to/from a target device
flash flash and, optionally, pave a connected device
reboot reboot a target fuchsia system
scp invoke scp with the build ssh config
serial attach to a serial console
sftp invoke sftp with the build ssh config
shell start a remote interactive shell in the target device
ssh invoke ssh with the keys from $FUCHSIA_BUILD_DIR/ssh-keys
wait wait for a shell to become available
screenshot takes a screenshot and copies it to the host
set-clock set the clock on target using host clock