[DCom] Auto Merge Double Post 2.4.0

• Fixed a bug where messages would not merge when the message length limit was disabled.
• Fixed a bug in the regular expression where merging of quoted messages was prohibited.
• Added a check to ensure that the "[automerge]" tag contains nothing but a timestamp.
• Added handling of the maximum number of attachments in a message.
• Code refactoring.

• Fixed a bug when merging messages when a message is not sent on the last page.

• Xenforo 2.3 support (minimum version)

• Fixed a bug when reaching the maximum message length
• Added option to disable merging when quoting a post
• Added a selection of forums in which you can turn off merging

• Fixed error sending message when user is not on last page

• Bug fix with empty line between merged messages