Option to add headers to access log

[philipianpearce]

Another little thing that was raised was the lack of headers in the access.log file whereas the dstats.log file has headers. Would it be possible to add headers so that when new fields are added to the access.log file it is easy for log analysis programs to add the new column by header name rather than position of column.

Originally posted by @Dalacor in #622 (comment)

[philipianpearce]

it is a good idea - will look at it for v5.5

[Dalacor]

Thanks. I will look out for it.