Seperate and Monitor... (Score 2, Interesting)

To prevent someone taking your work, have someone build the common libraries first, and then have someone else use that compiled library (obscurificated and with expiration date built in). You could also let them compile the code on your server and use remote desktop so you can see them working with the code, and then block the ports to make it harder for them to remove information from the computer. Good Luck...