"Return to Annotate" link on Panoptes opens new window instead of returning

[vrooje]

As a result I have a proliferation of windows with the project open... the link should, if possible, re-focus on the previous window. Or both the classification and Talk cross-links could open in the same window so that people are just switching back and forth.

I know I said in zooniverse/Panoptes-Front-End#946 that target=new should be the default behavior, but this is a pretty clear counter-example.