@SteveRichter: I worked on a backup solution before iCloud, OneDrive and Google drive, and although we stipulated that this was to backup home user files, you got businesses trying to backup their Sage Accounting databases, and email in their AppData folder.
As other have intimated, I will say it bluntly, don't use OneDrive to back source code because this is not what the tool has be designed to do. It is best for word documents, pdf's, images and music files. Use SVN (Visual SVN has very affordable tools that make working with SVN easier) or Git or TFS as mentioned before.
The whole point of saving source code in a versioning system, is being able to revert back to earlier check-in's seamlessly, this is the only option worth considering.
Do not use OneDrive for source control!