This is a propose fix for bug 1759

I have added a link "Terms and Conditions" in the "Sync account" screen. However, I think there is already one in the next screen for signing up. Moreover, I would propose the text "Don't have an account..." to be modified as now it looks like a button!

This is related to the following bug 1759:
https://code.google.com/p/ankidroid/issues/detail?id=1759&colspec=ID%20Type%20Priority%20Status%20Milestone%20Owner%20Summary