HEADERS filter improvement
Document recent additions
Cleanup PHP pass params by reference
[headers] remove more ephemeral headers
Add MAXREDIRECTS + options to HTTP

Add “maxredirects=n” to properties. Pass this (and prepare for other)
options to cURL GET and POST.
[length] Filter: Reduce retained "lengths" to 50

When [length] retains more than 50 length values, trim the array to 50.
Define MAX_LENGTHS to change how many.
Better log-transport shutdown
Consolidate "lengths" string processing

Consolidate processing of “lengths” in one place and create a DEFINE
that limits the number of lengths that are maintained by a filter.
Get SSL certs properly

Use libcurl properly to get SSL certificates. Eliminate CERT garbage
from “analysis” (error) stream.