freemount:  Add get_payload_{data,size}() copies
freemount:  Call get_payload_data() instead
freemount:  Honor frame.data in get_{data,size}()
freemount:  Add send_u8_frame()
freemount:  Send tinier integer frames if possible
Merge branch 'tiny-strings' into send-tiny-data
freemount:  Send tiny frames for one-byte strings
Merge branch 'send-tiny-data'