WEnotes to Chat with no from_user_name

[Jim Tittsler]

When a WEnote does not contain a from_user_name the integration with Rocket.Chat should fall back to the from_user.

Example: https://chat.oeru.org/channel/wenotes?msg=QbDXMysXRAmhwupgr

[Jim Tittsler]

WEnotestoChat: fallback to from_user

When a WEnote does not have a from_user_name, fallback to using the from_user value.

Fixes #7

→ <<cset 30f66ed7460b>>