I also think dict.cc
would be a good idea!
I took a look on the Page code of their searchpage,
and the id of the first word is "tr1
so by typing for example http://en-de.dict.cc/?s=to%20test#tr1
you directly get to the first result of "to test".
With this we didn't even need a real API.
The disadvantage is, that i don't know how to set the language you want to translate to.
But maybe we'll find out!