Consistency: espconn_regist_write_finish

[kolban]

The function called espconn_regist_write_finish() registers a callback function which will be invoked when the data has been copied to a write buffer or transmission has been completed. Now, let us compare this against the other callback registration functions which are:

o espconn_regist_sentcb
o espconn_regist_recvcb
o espconn_regist_connectcb
o espconn_regist_disconcb
o espconn_regist_reconcb

as you can see, the function called espconn_regist_write_finish() doesn't follow the same naming convention.

This post suggests that it be renamed to:

espconn_regist_writefinishcb

to be consistent with the other APIs.