Preview Button Changes  [#78477494]

 - put optional assignment to 'external' closer to the partial which
uses it:"app/views/browse/_preview.html.haml" , so that the code is
easier to read in both files.
Fix UI Issues in IE9,10

 - Clean Up of radio button css.
Fix security answer issue[#81650124]

 - Fix for security question answers not getting saved properly during
 the registration.

 - Fix password recovery for student.