Update Junit to 4.11

Junit 4.3.1 is quite old. I updated the junit library to 4.11 and added hamcrest. I think hamcrest isn't the best matcher framework anymore (look for assertj) but it's part of junit (since 4.7 or so)

Junit has a new licence. It's moved from CPL to EPL. I think this is no problem (and we don't ship it with our software) but i'm no lawyer.