Clean up routine names, don't pass capture_file into libwireshark.

Give all routines in epan/print.c that write a particular format a name
beginning with write_{formatname}.

If routines write columns, rather than the raw protocol tree, don't give
it a name containing proto_tree.

Get rid of empty preamble/finale routines.

For CSV, the preamble routine writes out column titles, so call it
write_csv_column_titles().

For C arrays, the body routine writes out raw hex data, so call it
write_carrays_hex_data().

capture_file isn't a structure defined by libwireshark, so don't make it
an argument passed into libwireshark.

Change-Id: I5a7e04de9382cf51a59d9d9802f815b8b3558332
Reviewed-on: https://code.wireshark.org/review/5536
Reviewed-by: Guy Harris <guy@alum.mit.edu>