oq-ui-client2/exposure_export.html:

When the exposure export dialog/form are loaded, hide the leaflet
popup.
oq-ui-api/geonode/exposure/views.py:

Fixed the population query; we were selecting the geometry instead of the
grid id ;-/
oq-ui-api/geonode/exposure/forms.py:

Shorter, more concise labels for admin level widgets.
oq-ui-client2/exposure_export.html:

When selecting a bounding box, clean up previous export form elements,
otherwise we will leak them and cause problems. For example, failing to
do this will result in inability to do multiple selections and exports.
oq-ui-client2/exposure-export-wizard-1.html:

Changed "Submit" button to "Download" button.