oq-ui-api/geonode/exposure/views.py:

Actually render the population export form. Before, we were just
sending back a template response with no form. Which isn't very
helpful.
oq-ui-client2:

Added download button ajax spinner gifs to exposure_building_form.html
and exposure_population_form.html.
oq-ui-client2/src/exposure/exposure_export.js:

Show/hide the download button ajax spinner gif (when the export forms
are displayed). Showing/hiding occurs appropriately within the tool
workflow.