Blender Git Loki

New feature: imporant missing option for use of Libraries: access to to the
file path where library is read from.

In Outliner, choose new view mode "Libraries". A ctrl+click on the library
name then allows to change the file name or path. Note that when you change
the file name, nothing is being re-read or re-linked. Only after saving the
.blend file and reading it back the new library is used.

This feature allows to cleanup library usage. You can make files relative,
or reorganize a project. Just keep in mind that you cannot use this feature
to fix .blend files that link to non-existing other files. That because the
lost data is actually not read at all, so cannot be saved either.

Currently, library errors are only printed in the console... quite
important to keep track of when using Libraries.

Implementation note: this Outliner view mode can become expanded to a full
"Database view", showing something similar as SHIFT+F4 databrowse does now.