ESP Examples (2016-10-28)

Append, don't replace, previous input on new input.

Previously, we were overwriting the incoming data buffer (input_data_)
each time the input stream called onDataIn(). Instead, append the new
data to the existing data, so that we don’t lose data if the callback
is called more than once before we can process the data.

When processing the data, only lock the input_data_ buffer long enough
to copy its data to a local variable, rather than for all of the
processing.

On pause or resume, lock on the input_data_ buffer before clearing it.