root: remove inactive download button (#134)

We have no container download functionality yet. We'll add the button
again if #41 is implemented.
container: remove Download and Show buttons (fixes #135)

These buttons make no sense when you select more than one item: they
will simply link to the first item selected.

The same functionality is found by clicking the object and using the
button found on the per-object page.
object: rename Show button to Edit (fixes #136)
Merge pull request #137 from mgeisler/cleanup-buttons

Cleanup buttons