So far tud_vendor_n_write() always flushed data.
It requires to have whole vendor packed constructed
before in one buffer.
With this change data do get flushed when endpoint size
is filled on write, when there is no enough data to
fill endpoint data is not sent and subsequent calls to
write functions can add more bytes.
Vendor code needs to call tud_vendor_n_flush() when packet is
ready to be sent.
Returns the RT driver to the function state of previous iteration, which
did not support the will_detach. Behavior should be fine without this
feature. This removes much of the added bloat to track state, and
handle requests in the APP_DETACH state which is no longer required.
Removes the optional bloat added to the RT driver, such as responding to
GETSTATE requests.
Fixes the DFU Mode to extract the attr bits from the functional
descriptor when opened.
Fixes some incorrect bitwise if checks.
Also, updates some naming of functions to be consistent with the rest of
the library.
