Postbox specifications

- Updated versions of the Lightning Add-on for Mac and Windows
- Fixed an issue where IMAP attachments could get corrupted on download for Ggmail and Exchange servers
- Added ability to drag and drop an eml file into the message list pane to copy a message into a folder
- Fixed an issue with the new account setup wizard when trying to create a POP3 account
- Fixed an issue where filters on subject would fail to fire correctly
- Fixed an issue with Creating a Filter by right clicking on a Favorite contact in the focus pane
- Fixed an issue that prevented several Mozilla dictionaries from being installed into Postbox on Windows
- Added ability to redirect and resend eml files opened in Postbox
- Added a keyboard shortcut for marking a message as Pending (Shift + M)
- Stability improvements