To grab the dev version just go to
https://github.com/reefangel/Libraries/tree/dev
and click on "Download ZIP" on the right and unzip into your reef angel libraries directory. Mine is under My Documents\Arduino\.
If you want to contribute code you can make a github account, then click "Fork" on the top right at
http://github.com/reefangel/Libraries/ That gives you a copy of the code to play with.
I then use the Github for Windows client to work on the code:
https://windows.github.com/ You drag the copy of Libraries from your repository to the client once you start it up and log in.
If you want to add code you'd pick the dev branch on the github client, make a new branch by typing in a name for the change you made into the branch selection box. For instance, for this one I made a branch called "credit-for-else-mode" and put two lines into Globals.cpp:
https://github.com/amunter/Libraries/tr ... -else-mode
Here is the commit that I did:
https://github.com/amunter/Libraries/co ... 75db63c468
Then you make changes to the files on your hard drive and check them in. Make sure the branch is published by clicking the Publish link on the top right of the github for windows client.
Once you're satisfied you go to the website and do a pull request to Roberto. Pick your new branch from the droplist and pick "Pull Request" via the green button to the left of the branch picker. It will come up with a pull against reefangel/master, but click the "Edit" button to change it to a pull against reefangel/dev. Type in something so Roberto knows what you're trying to do and wait for him to go over your changes. He tends to let it sit for a while which helps me out because I'll often have like 1 more or 2 more little changes you end up making...
If Roberto makes changes to the dev branch which you want to get back into "your" dev branch you can open the Github Windows client, make sure dev is selected on the drop list, then right click the repository name on the left: "Libraries" and pick "Open in Git Shell" It will open a text window with [dev] on the prompt in green. Then do
git fetch upstream
git merge upstream/dev
git push
and you'll have everything up to date with Roberto's code. If you've been making your own changes on /dev (which you shouldn't do, probably, you should probably be working on branches which are copies of /dev) you may get conflicts, which can be tough to figure out, but you'll figure it out if it happens.
Once Roberto has merged in whatever changes you made and submitted to him in your pull request you can delete that branch and merge upstream/dev again to get them into your dev branch.