Implement startup frame setup
Implement startup frame setup

Refactor some of the common network sending code into a procedure that
will try its best and invalidate the file descriptor sending fails.

Fix various bugs on inspection; more of these will probably become
apparent when writing the protocol rendering tool.

Also, tidy up the static function declarations to make them all
apparent at the top of the file, now that the implementation seems to
have gelled more.

Signed-off-by: Daniel Farina <3d0f3b9ddcacec30c4008c5e030e6c13a478cb4f@heroku.com>

logplex/pg_logfebe,logplex/pg_logfebe