vcr: include some text chunks in the png destHEADmaster

If the caller has some textual information to embed in the PNG
metadata, it should be able to embed it.

This adds three:

timestamp: always populated with the current time
name: always populated with --name arg, or empty
payload: made available for customized usage

payload is aimed at strobe users who have some context associated
with the strobe request they'd like to embed in an easily
machine-readable location attached to the png file.

0 files changed, 0 insertions, 0 deletions