Detached doc from uploaded_docs[id].

This is not the best way to do this, but a simple grep will show me all
occurrences of this inferior pattern, to be fixed in an extra commit.
I need those two detached because doc will be modified according to the
uploaded data and I want uploaded_docs to store the previous version of it.
Stored document ids as feature.id.

This will come in handy later because I won't need to reference
uploaded_docs[d]. This version does not work right now!!!
Changed invalid uploaded_docs[d].id with feature.id.

The good thing is that feature.id is not part of feature.properties, so it goes
undetected if documents are uploaded. The other good thing is that I don't need
the stupid index anymore and I end up with a simpler script.
The revert button is still not working correctly, however!!! I am in the middle
of if!!!!
Presumably this fixes the revert button (untested yet).

New documents are simply deleted and existing documents are restored to their
previous version, except for the _rev field, which is updated on every bulk
upload.
I will test this next week because it is CLOSING TIME!! OPEN ALL THE DOORS AND
LET YOU OUT INTO THE WORLD!!
Added missing 'rev' property to feature.

I've missed to store revisions of new documents somewhere. Since feature
collections are agnostic to any other fields except for 'properties' and
'geometry', this would be the place to go, I presume.
Moved rendering "#modify div" into build_modify().
Fixed uncaught error on submit->reduce->revert->submit.

"#div modify" needs to be refreshed to represent
feature.properties.GeoJSON_clone.
Minor optical changes.

That is, a new line for every function and I used 'show_fields' instead of
'build-whatever'. Now it's starting to look like a little less of retarded
scripting.