I think you can still move your code to a released version of Copter. There are a few steps to it and you will have to troubleshoot if you see some compile errors.
First you need to check out the last commit where the Copter 3.3.3 was released.
git checkout acf2e10
This moves the head to that point in the master. Now you need to make a new branch for all of your changes
git branch (new_branch_name)
where (new_branch_name) is the name of your new branch
Now you have to make sure you are on that branch
git checkout (new_branch_name)
Lastly you have to merge fhedberg's commits for the Dual-heli
So you would use the cherry pick command
git cherry-pick (commit_hash)
where the (commit_hash) is a 7 character alpha-numeric. the first one in is dual heli commits is ffd625b
You will have to get the rest of the commits from his pull request
fhedberg commits for dual heli
Cherry pick them in the order of date in case some changes were made to earlier commits
The 7 character alpha-numeric is listed beside the commit on the right. After that do a "git status" to see that everything was committed. I think the cherry pick should commit them as well.
Then you will have to start compiling and fix compile errors if any occur. Good luck!
Hope this helps.