Thunderbird 49.0 Beta 1

# New
* Import settings from Becky! Internet Mail
* In compose, allow separate options for initial mode (Paragraph or Body Text) and behavior of Enter key.
# Changed
* Permanently remove Eudora import.
* Removed compose window recycling.
* Mac OX X 10.6, 10.7, and 10.8 are no longer supported.
# Fixed
* Folder view arrows were missing.
* Menu items for "Edit draft" functionality were missing
* Plain text composition had wrapping issues.
* Attachment reminder not showing in various cases.
* When attachment unavailable, compose showed endless "Attaching..." message instead of error.
* Table properties stopped showing with double-click of table cell in compose.
* Threading broken when editing message draft, due to loss of Message-ID
* "View as plain text" displayed converted HTML part even when plain text part exists.
* Certain malformed or complex header values displayed incorrectly.
* Mail saved as template copied In-Reply-To and References from original email.
* Additional spaces were inserted when drafts were edited.
* "Edit as New Message" on a received message pre-filled the Sender as the author rather than the current user.
* Custom headers (like Disposition-Notification-To) were not set correctly.
* Recipient addresses were shown in wrong color in some circumstances.
* Display name was truncated if no separating space before email address.
* Embedded image with source URL with ? led to incorrect image reference