Make timestamp headers optional

[FrostyX]

I lurk on some low-traffic channels and there seem to be more timestamp headers than the actual messages. I want to disable them.

[alphapapa]

Thanks for bringing this up.

This patch only adds one line, but it touches a lot of them, and there may be a simpler way: see the variable ement-room-timestamp-header-delta.

[FrostyX]

Thank you for the feedback @alphapapa, so it seems that

(setq ement-room-timestamp-header-delta most-positive-fixnum)

basically disables timestamp headers? Do you find any issue with this configuration? I'll close the PR if this is a good way to do this.

[alphapapa]

AFAIK that would be the preferred solution, yes.

[FrostyX]

Thank you, in that case, I am closing this PR.