quick UI for handling multiple USB devices

Makes list of unmounted removable devices.
Displays forms for mounting,unmounting if unmounted,mounted
devices are present.
UI could use some work.
gitolite_info func moved to DDR.dvcs module; now takes argument
report bad RSA key; add TODO

The storage checker function would fail if the server user's
public/private keys don't work with Gitolite, but it would not
alert the user to that fact.  Add error message.

Note that function will report as unreadable if there are no
collections for the repo/org combination.
don't log quite so much
Merge branch 'master' into 068-backup
Merge branch 'master' into 068-backup

Conflicts:
	ddrlocal/storage/decorators.py
Merge branch 'master' into 068-backup

Conflicts:
	ddrlocal/storage/decorators.py
active device indicator form on storage-index page

This commit adds another form to the storage-index page, which
indicates which removable device, if any.
The actual mechanism really should live at the ddr-cmdln level.
oops, forgot some imports...
wrappers to the DDR removables(_mounted) funcs with added info

The removables_mounted function adds a flag indicating whether
the removable is the target of the MEDIA_BASE symlink.
Note: Had to rename some vars in storage.views to prevent name
clashes.
don't need to specify path for rm_media_symlink
rework active-removable form; add ability to select active rem
split the storage-index view into several simpler view

This view was handling GET and POST for mounting and unmounting
devices as well as changing the active device, and was getting
convoluted.
Merge branch 'master' into 068-backup

Conflicts:
	ddrlocal/webui/__init__.py
added access file extension to settings

This is used by ddr syncgroup
Merge branch 'master' into 068-backup
Merge branch '068-backup'
Merge branch 'master' of https://github.com/densho/ddr-local
Merge branch 'master' of https://github.com/densho/ddr-local