Send MessageLoaded every time Option

[igerzog]

I think it will be useful to manually choose how to track opens - on first open only or on every open.

[iammattmartin]

Could be flawed though if you opt for "first" because some providers pre-load images via a proxy and that counts as "opened" before the message has even been seen.

[igerzog]

To tell the truth I need the second variant. Cause the open webhook is posted only one time now.