Turn tab into space for copying

http://manage.dimagi.com/default.asp?104522#794142

This replaces the tab character with a space when doing a TSV export. Can't really do it another way because the expectation is that a user needs to copy it to put it into excel.

I also thought about replacing the tab character with a space in the input, but I figured if they went through the trouble of inputting a tab into that, then they expect to have it show up like that in the app.